“Consulting Services for the Assessment of the Multi-hazard Vulnerability of Priority Cultural Heritage Structures in the Philippines” FINAL REPORT September 2016 Final Report QUALITY CONTROL Name Date Original Revision 1 Revision 2 Dr. Arch. Patriza Barucco, Prof. Eric Zerrudo, Eng. Andrea Giannantoni, Prepared by: Eng. Sergio Lagomarsino, Eng. V. 30/06/2016 19/07/2016 23/09/2016 Fanciullacci, Arch. C. Bronzino, Eng. G. Paci, Arch. F. Ballotti Verified by: Dr. Arch. Patrizia Barucco 04/07/2016 22/07/2016 26/09/2016 Controlled by: Dr. Eng. Daniele Fanciullacci 04/07/2016 25/07/2016 29/09/2016 2 Final Report Contents 1. INTRODUCTION AND SUMMARY .................................................................................................................... 5 1.1 Project Background ................................................................................................................................. 5 1.2 Project summary ..................................................................................................................................... 6 1.3 Scope and summary of this Final Report ................................................................................................. 7 1.4 List of persons who contributed to this document ................................................................................. 8 2. DEVELOPING STANDARDS FOR MULTI-HAZARD RISK ASSESSMENT AND REDUCTION OF BUILT HERITAGE ......................... 9 2.1 Introduction ............................................................................................................................................ 9 2.2 Seismic assessment and preservation of cultural heritage structures .................................................. 10 2.3 Basics of PERPETUATE guidelines .......................................................................................................... 12 2.4 Decision-making on strengthening interventions ................................................................................. 16 3. ANALYSIS OF OPTIONS FOR REDUCTION OF MULTI-HAZARD RISKS IN SELECTED BUILDINGS IN BOHOL ......................... 21 3.1 Introduction .......................................................................................................................................... 21 3.2 Dimiao Church ....................................................................................................................................... 21 3.2.1 Technical background ................................................................................................................. 21 3.2.2 Retrofitting Options .................................................................................................................... 23 .................................................................................................................. 28 3.2.3 Comparative Analysis 3.3 Alburquerque Church ............................................................................................................................ 29 3.3.1 Technical background ................................................................................................................. 29 3.3.2 Retrofitting Options .................................................................................................................... 31 .................................................................................................................. 34 3.3.3 Comparative Analysis 3.4 Panglao Watchtower ............................................................................................................................. 35 3.4.1 Technical background ................................................................................................................. 35 3.4.2 Retrofitting Options .................................................................................................................... 37 .................................................................................................................. 40 3.4.3 Comparative Analysis 3.5 Recommendations on interventions already designed for the Tagbilaran Capitol ............................... 42 3.5.1 Structural survey and crack pattern ........................................................................................... 42 3.5.2 Description of existing project .................................................................................................... 50 ......................................................................... 55 3.5.3 Structural improvements to the existing design 4. RECOMMENDATIONS FOR IMMEDIATE AND MEDIUM-TERM RISK REDUCTION MEASURES FOR PRIORITY STRUCTURES ... 69 4.1 General Concepts .................................................................................................................................. 69 ............................................................................. 69 4.1.1 Summary of the Priority Structures Analysed 4.1.2 Summary of main weaknesses found in the 16 Priority structures ............................................ 69 4.1.3 Notes on risk reduction strategies for main heritage structures in the Philippines ................... 74 3 Final Report 4.1.4 Collection of typical intervention details .................................................................................... 77 ................................................................................ 119 4.2 Recommendations for the 16 priority structures 4.2.1 Loboc Church ............................................................................................................................ 119 4.2.2 Loboc Tower ............................................................................................................................. 121 4.2.3 Loboc Mortuary Chapel ............................................................................................................ 123 4.2.4 Albuquerque Church ................................................................................................................. 126 4.2.5 Alburquerque Convent ............................................................................................................. 129 4.2.6 Cortes Church ........................................................................................................................... 131 4.2.7 Cortes Convent ......................................................................................................................... 135 4.2.8 Dimiao Church .......................................................................................................................... 137 4.2.9 Dimiao Convent ........................................................................................................................ 140 4.2.10 Panglao Church ....................................................................................................................... 141 4.2.11 Panglao Watchtower .............................................................................................................. 143 .......................................................................................................... 145 4.2.12 Punta Cruz Watchtower 4.2.13 San Agustin Church ................................................................................................................. 147 4.2.14 San Agustin Convent ............................................................................................................... 151 4.2.15 Manila Metropolitan Theatre ................................................................................................. 153 Annexes Annex 1. Site Investigation Campaign A. Implementation procedures of site investigation campaign 1. Introduction 2. Reference framework 3. Actions undertaken to prevent negative impacts during the testing campaign B. Reports on implemented tests 4. Albuquerque Church 5. Cortes Church 6. Dimiao Church 7. Panglao Watchtower C. Test campaign attendance sheet Annex 2. Numerical Analysis of Retrofitting Options 1. Dimiao Church 2. Albuquerque Church 3. Panglao Watchtower Annex 3. Analyses Of Options For Reduction Of Multi-Hazard Risks In Bohol 1. Dimiao Church 2. Albuquerque Church 3. Panglao Watchtower 4 Final Report 1. I NTRODUCTION AND SUMMARY 1.1 Project Background In 2013 an earthquake struck Bohol Island in Central Visayas and the super Typhoon Yolanda severely affected 14 provinces in the Visayas. Several centuries-old heritage structures were seriously damaged, with some even totally destroyed. The Department of Tourism (DoT) expressed the urgent need to improve the resilience of these types of structures to natural disasters to ensure that their cultural, historical and economic value is sustained and continues to contribute to the overall development of the areas where they are located. At the request of DoT, the World Bank, with funding from the Global Facility for Disaster Reduction and Recovery (GFDRR) financed a detailed vulnerability assessment of selected cultural heritage structures to identify, prioritize and provide initial cost estimates for risk reduction investments for structural strengthening and restoration. The World Bank mobilized ARS Progetti SPA from Italy in collaboration with the University of Santo Tomas Graduate School Center for Conservation of Cultural Property and Environment in the Tropics and specialist engineers from the De La Salle University to undertake the vulnerability assessment. The main objective of the service was to assist the Department of Tourism in assessing and identifying strategy to reduce the vulnerability of cultural heritage structures to multiple natural hazards, including earthquake, typhoon, flood, etc. The project was implemented in three subsequent phases: in the first one, historic buildings in the nominated pilot areas were visited and studied, organized by architectural typologies and a final selection of priority structures was proposed. In the second phase, multi-hazard vulnerability assessment of 16 priority structures was carried out, and the implemented methodology was described in the “Multi-Hazard Assessment Manual of Philippines’ Built Heritage”1. Finally, in the third phase, a deeper study of selected structures was implemented and immediate and medium term risk reduction measures identified; furthermore, a set of risk reduction measures was compiled per architectural typologies. The exercise constitutes a reference to deepen the assessment criteria and procedure, as an important step in shifting the focus from emergency response to preparedness, mitigation and prevention. The objective of the Manual was to provide an overall framework for vulnerability assessment and a specific analytical method implementable with limited inputs in terms of time and resources, while strengthening the capacity of national professionals and officials regarding the applied procedures and methods. The described approach has been chosen on the basis of the assignment framework and of available data; therefore, the guidance provided is not meant to suggest an unconditional approach, rather one of the possible methods to practically respond to the need of planning and undertaking measures to reduce risks and mitigate impacts on the Philippines’ built heritage. Earthquakes constitute the main cause for loss of historic buildings, and their protection poses a great challenge because the structures were not based on an engineered design and underwent transformations and additions over time. Therefore, it is necessary to refer to accurate models able to simulate the non- 1 ARS Progetti Report, 2016 5 Final Report linear behaviors of the masonry, and a well-defined assessment procedure, which considers not only the use of the building and safety of people but also the conservation of all the tangible and intangible values of the monument. Predicting the damage to the built environment for a given earthquake scenario constitutes a crucial tool not only for emergency management, but also for risk mitigation, and for carrying out cost/benefit studies for structural intervention. The ultimate aim shall be to define, even for old masonry structures, an assessment procedure repeatable and verifiable, as a decision-making support system. The Philippine Standards of Conservation2 represents a unique occasion of moving forward in such a direction, outlining, in an oriented practice tool, the methodology and procedure for the assessment of natural hazards risk to cultural heritage assets and design of interventions. The preservation of historic buildings must guarantee their safeguarding against decay, natural hazards and extreme events, without losing in authenticity and usability. A reliable assessment procedure is the starting point to respect the principle of “minimum intervention” while obtaining a higher structural safety. 1.2 Project summary The main tasks of this assignment were: • prioritize and recommend specific structures for detailed vulnerability assessment • assess the vulnerability of selected cultural heritage structures • recommend options to mitigate the impacts of earthquakes and other natural disasters on the assessed structures. The activities were implemented from July 2015 to June 2016 as follows: • Task 1 (July – September 2015): Collection of available documentation, background reading, research on historical records o and available bibliography; o Stakeholders consultation, field visit, review of pilot areas and elaboration of a tentative list of priority structures; o Opening Workshop. • Task 2 (September 2015 – April 2016) oFinalisation of selected priority structures list; oData collection on selected priority structures; oField survey for multi-hazard vulnerability assessment; oMulti-hazard vulnerability assessment of 16 priority structures; oElaboration of a multi-hazard vulnerability assessment manual; oImplementation of 2 training sessions on the vulnerability assessment process. • Task 3 (January – June 2016) o Implementation of a testing campaign and structural survey; o Analysis of options for reduction of multi-hazard risks in selected buildings in Bohol; 2 Currently under development by the NCCA in collaboration with NHCP and NM 6 Final Report o Recommendations for Immediate and medium-term risk reduction measures for priority structures; o Elaboration of a web database. Field missions were carried out according to the following schedule: • August 1-8: stakeholders meetings, site visits • August 29- September 5: visual survey of tentative priority structures, opening workshop • October 13- 23: Field survey of priority structures for vulnerability assessment • November 21- 24: Field survey for wood identification • December 26-29: Field survey for integration of missing data • January: Implementation of onsite testing campaign • March 7-10: training workshop in Manila • May 10-12: training workshop in Bohol A total of 4 workshop were organised as follows: • Opening workshop (September 3-4) • Training workshop on multi-hazard vulnerability assessment, Manila (March 7-10) • Training workshop on multi-hazard vulnerability assessment, Bohol (May 10-12) • Final workshop (June 22) The outputs produced were: Task 1: Inception Report and detailed assessment methodology Task 2: Multi-Hazard Vulnerability Assessment Manual of Philippines’ Built Heritage Multi-Hazard Vulnerability Assessment of 16 selected Priority Structures Task 3: Analysis of options for reduction of Multi-hazard Risks in selected buildings in Bohol (current report) Recommendations for Immediate and Medium-Term Risk Reduction Measures for Priority Structures (current report) 1.3 Scope and summary of this Final Report This final report is the last output of those foreseen by the Terms of Reference, and is submitted upon conclusion of Task 3. Based on the analysis and findings produced during Tasks 1 and 2, this Report focuses on practical steps for reducing risks and prioritizing actions on cultural heritage assets. In the perspective of establishing a systematic process to increase the disaster resilience of built heritage within the overall investment strategy for the tourism sector, this Report provides also some recommendations for developing standards for multi-hazards risk assessment and reduction, as well as a methodological and practical approach for planning priorities. This general discourse is conducted together with a detailed analysis of selected heritage structures. This report is structured as follows: Chapter 2 is a contribution to the development of standards for seismic risk assessment and reduction of built heritage. 7 Final Report Chapter 3 describes the consolidation proposals drafted for Dimiao Church, Alburqueruqe Church and Panglao Watchtower, and advices on conservation design and works under implementation on the Tagbilaran Capitol in Bohol. Two alternative consolidation strategies are identified for each of the buildings in order to reduce their vulnerability removing the constructive critical issues intrinsic in the technique of realization of Philippine masonry. Chapter 4 lays out recommendations for immediate and medium-term risk reduction measures. After summarizing the recurrent types of weaknesses detected in the selected priority buildings, an overall intervention strategy is drawn and integrated with a collection of typical details to address the different structural damages identified. Finally, general guidelines for intervention on the 16 selected priority buildings are provided, with the indication of immediate and medium-term measures for risk reduction. 1.4 List of persons who contributed to this document Daniele Fanciullacci, Project Director, Chief Executive, ARS Progetti Patrizia Barucco, Team Leader/Project Manager, Ph.d. Conservation architect, Head of Heritage Department, ARS Progetti Eric B. Zerrudo, Deputy Team Leader, Director of CCCPET (Center for Conservation of Cultural Property and the Environment in the Tropics), University of Santo Tomas Andrea Giannantoni, Chief Structural Engineer for Historic Buildings, ARS Progetti Consultant, Professor of Structural Restoration, University of Ferrara Giuseppe Paci, Structural Engineer, Specialist in Structural Consolidation, Assistant to the Chief Engineer Fanny Ballotti, Conservation Architect, Specialist in Structural Consolidation, Assistant to the Chief Engineer Viola Fanciullacci, GIS Specialist and Hydraulic Engineer, Assistant Team Leader, ARS Progetti staff Cristina Bronzino, Conservation Architect, Assistant Team Leader, ARS Progetti staff Furthermore Sergio Lagomarsino, Prof. of structural engineering at the University of Genoa-Italy, member of the Drafting Panels of the Italian seismic code and the Italian Guidelines for cultural heritage in seismic areas, contributed Chapter 2 “Developing standards for multi-hazards risk assessment and reduction of built heritage”. 8 Final Report 2. D EVELOPING STANDARDS FOR MULTI - HAZARD RISK ASSESSMENT AND REDUCTION OF BUILT HERITAGE Contribution by prof. Sergio Lagomarsino3, University of Genoa (Italy) Foreword The NCCA in collaboration with NHCP and NM is currently developing the Philippine Conservation Guidelines. A section of these standards should deal with multi-hazard risk assessment and reduction. The task can also be framed within the provisions of the ''Philippine Disaster Risk Reduction and Management Act of 2010", specifically, the provision to “adhere to and adopt the universal norms, principles, and standards of humanitarian assistance and the global effort on risk reduction as concrete expression of the country's commitment to overcome human sufferings due to recurring disasters”4. The following section provides recommendations by Prof. Lagomarsino, one of the main contributors to the Italian “Guidelines for the seismic vulnerability assessment and risk reduction of built heritage”, issued by the Italian Ministry of Cultural Property and cultural activities. These guidelines can be considered as a benchmark on the subject. 2.1 Introduction Historical constructions are an important part of the cultural heritage, because of the architectural value and examples of building techniques. Their conservation over the centuries is a duty of our society, in order to pass on to future generations. They are subjected to slow environmental processes and exposed to both high-frequency, low-impact natural hazard events, as well as high-impact, lower-frequency disasters. It is worth noting that the safety of ancient constructions under ordinary static loads or actions, which are constant or frequently-occurring has been demonstrated over time. The assessment of the present conditions of a building can be made by comprehensive interdisciplinary knowledge, based on historical notes, technological survey, non-destructive investigations and the interpretation of crack patterns and decay. Slow processes might affect the current stability of buildings in many ways: i) material deterioration; ii) anthromorphopic modifications, particularly in the urban environment; iii) climate and environmental changes. Monitoring is the primary mitigation tool in all three cases, both through advanced instruments and qualified visual inspections, in order to detect when interventions are needed. Usually, deterioration processes can be slowed down and serious damage prevented by periodic maintenance. 3 Full professor of Structural Engineering at the University of Genoa, since 2000. He has coordinated the European project PERPETUATE (www.perpetuate.eu), on the seismic assessment and protection of cultural heritage assets. He has served on the drafting panels of the Italian seismic code and the Italian Guidelines for cultural heritage in seismic areas. At present he is member of the Project Team 3 that is working on the revision of Eurocode 8 “Design of structures for earthquake resistance” - Part 3: “Assessment and retrofitting of buildings”. He has developed the survey form for post-earthquake damage assessment of ancient churches, used by the Italian Civil Protection Department and, at research level, in many other countries, such as Spain, Portugal and New Zealand. 4 'The Philippine Disaster Risk Reduction and Management Act of 2010, Section 2. Declaration of Policy, point a). 9 Final Report On the contrary, the preservation from natural hazards requires a preventive assessment of the specific vulnerability and risk, which cannot be based only on a qualitative approach and the observation of the building behavior in the past. In particular, earthquakes represent the main cause of damage for masonry structures and, due to the high return period of maximum credible earthquakes in the area, a direct proof of safety is usually not available for the specific case. Indeed, after any strong earthquakes the necessary restoration requires strengthening and, often, partial reconstruction of elements, with a significant loss of the authenticity of the building. Therefore, it is necessary to have measures in place to implement a preventive policy, which takes into account conservation requirements. Damage occurred due to previous small earthquakes might suggest the possible collapse mechanism that the building would experience in the case of a strong motion, but a reliable seismic assessment cannot be without quantitative models. The seismic assessment of existing buildings is a complex task, basically for two different reasons: i) the difficulty of interpreting and modeling the seismic response, because they have been designed without aseismic provisions and, in the case of ancient masonry structures, by an empirical approach; ii) the difficulty of acquiring as-built information on material parameters and structural details, due to their spatial variability in the buildings and the need of avoiding invasive investigations. Earthquakes also proved that strengthening interventions adopted in the last century are invasive and sometimes are either not effective or even increase the vulnerability. Thus, proper methods of analysis and verification procedures are required for the seismic assessment and the design of interventions, with the aim of achieving risk mitigation of cultural heritage. Finally, it has to be stressed that the use and exploitation of cultural heritage constructions represents a warranty for the conservation, because it guarantees permanent future monitoring, even if sometimes interventions and transformations are required. A detailed assessment through proper procedures and models allows for the avoidance of invasive and useless interventions. 2.2 Seismic assessment and preservation of cultural heritage structures The United Nations Educational, Scientific and Cultural Organisation (UNESCO) constituted in London on November 16, 1945, aims at continuing the work begun decades before by the League of Nations, UNESCO articulated its commitment to the concept of a common cultural heritage and to the idea of conserving this heritage through international collaboration and cooperation in its constitution [1]. In 1957 UNESCO was involved with organizing the First International Congress of Architects and Specialists of Historic Buildings, which took place in Paris and wherein a recommendation to create an “international assembly of architects and specialists of historical buildings” was met with approval. In May 1964 UNESCO’s executive board adopted a resolution with an identical goal to that of the 1957 Paris congress and, in the same year, during the Second International in Venice, Italy, UNESCO put forward a resolution and draft status providing for the establishment of an international non-governmental organization for monuments and sites, named the International Council on Monuments and Sites (ICOMOS), responsible for providing expertise in the form of consultants to UNESCO. The resolution was adopted along with twelve others, the first of which become the International Charter for the Conservation and Restoration of Monuments and Sites, known as the Venice Charter. In June 1965 the Venice Charter was ratified and the ICOMOS was officially founded in Warsaw, Poland. From its foundation, ICOMOS has established more than twenty-five International Scientific Committees on various themes and issues related to cultural heritage, which undertakes research, 10 Final Report develops conservation theory, guidelines and charters and fosters training for better heritage conservation [2]. The Venice Charter is the first text wherein the concept of heritage is defined. In its introductory section it can be read that “Imbued with a message from the past, the historic monuments of generations of people remain to the present day as living witnesses of their age-old traditions. People are becoming more and more conscious of the unity of human values and regard ancient monuments as a common heritage. The common responsibility to safeguard them for future generations is recognized. It is our duty to hand them on in the full richness of their authenticity” [3]. In other words, heritage as a concept can be defined as the collection of things which relates people to who they are, where they have come from, and why they are the way they are. According to [4], the documents following the Venice Charter concentrate on two different issues: (i) the definition of the general principles for the identification of new fields of conservation (addressed in the 1971 UNESCO Convention on the safeguarding of wetlands and in the Charter of the Council of Europe in 1972, wherein as a limited and fragile resource the soil is proposed as heritage); and (ii) the attempt to integrate the principles of safeguarding with the control systems of the territory and of the economic and social development [4]. In the 1972 UNESCO Convention on the Protection of World, Cultural and Natural Heritage [5], the expression “cultural heritage” is used to refer monuments, wholes and sites of “exceptional universal value from the point of view of history art and science”, a line followed later in the 1987 Charter for the Conservation of Historic Towns and Urban Areas (Washington Charter) [6], known as Washington Charter, where the need to protect historic cities is clearly stated. It is worth adding that the concepts of tangible and intangible values as the object of protection were recognized for the first time in this document. Another document worth highlighting on this issue is the 1979 Burra Charter [7], where it is stated that the conservation of the cultural significance of a site, due to its aesthetic, historic, scientific or social value, must be safeguarded and protected. Despite its great influence, cultural heritage has not often had the recognition it deserves. In fact, throughout history there have been many theories on the treatment and protection of cultural heritage, particularly to buildings, some of these have been considerate and respectful, whereas others have been destructive and oblivious [8]. Regarding structural preservation, in particular with reference to seismic risk, international standards (Eurocode 8-Part 3 [10], ASCE/SEI 41/13 [11]) adopt for the evaluation of existing buildings the Performance-Based Assessment (PBA), which considers several Performance Levels (PLs) that must be fulfilled in the occurrence of corresponding earthquake hazard levels (defined by the return period). The need to check the achievement of PLs that are close to structural collapse strongly recommends the use of static nonlinear models and displacement-based procedures for the assessment, because the use of linear analysis with the behavior factor approach is not reliable enough. The specific case of cultural heritage assets is treated in some recommendation documents ([9], [12] and [13]), which are not only aimed at seismic vulnerability but consider all possible causes of damage and deterioration, with the aim of making a diagnosis and designing a rehabilitation intervention. They point out the complex configuration of these kinds of structures, also due to the relevant transformations that have usually occurred over time, as well as the difficulty of adopting a proper modeling strategy. All these recommendations stress the importance of the qualitative approach, founded on historical analysis, the accurate investigation of structural details and the interpretation of seismic behavior, on the basis of observed damage to the building (due to previous events, if any) or to similar structures. 11 Final Report It is worth noting that a preliminary assessment is usually sufficient for the diagnosis in many critical situations, such as material deterioration or soil settlements. On the contrary, the evaluation of seismic vulnerability without the support of calculations is overambitious, because the qualitative approach can only suggest which is the expected seismic behavior and the historical analysis is not sufficient to prove the building’s safety. This is the reason why the Italian Guidelines for the seismic assessment of cultural heritage [14] clearly states that it is not possible to avoid a quantitative calculation of the structural safety, even if models have to be based on accurate knowledge and the results can be adjusted by taking into account qualitative evaluations. The PERPETUATE project [15], funded by the European Commission, has developed guidelines that are coherent with the latter cited recommendations but frame the problem of the seismic assessment of cultural heritage assets and design of interventions within the PBA approach, outlined by the international standards for current buildings (Eurocode 8-Part 3, FEMA 356). The aim is to define, even for complex cases of old masonry structures, an assessment procedure repeatable and verifiable, which leads to the quantitative evaluation of safety levels, taking into account historical and qualitative information. This PERPETUATE guidelines offer the general methodological path and operative tools for the assessment of different historical architectural assets; a classification is proposed which is related to the different types of seismic behavior, considering both building morphology (architectural shape and proportions) and technology (type of masonry, horizontal diaphragms, effectiveness of wall-to-wall and floor-to-wall connections). It consists of six architectonic classes: A) box-type buildings; B) assets analyzable by independent macroelements; C) slender structures analyzable by monodimensional models; D) arched structures; E) massive structures; F) block structures subjected to rocking. Different modeling strategies can be adopted for describing the seismic behavior of each kind of asset. The seismic assessment considers also the presence of artistic assets that have to be preserved; three different classes have been introduced: P) artistic structural elements (e.g. carved stone columns); Q) artistic assets strictly connected to structural elements (e.g. frescoes, mosaics, stuccoes); R) artistic assets that are independent elements. Moreover, the problem of seismic local mechanisms is treated, which have to be taken into account in all the above- mentioned architectural asset classes, in order to assess the vulnerability of single elements that are not described by the structural models used for the assessment at global scale. This local analysis is also necessary for the verification of artistic assets of class R. 2.3 Basics of PERPETUATE guidelines Seismic Performance-Based Assessment (PBA) of an existing building checks if the construction is able to fulfill some selected Performance Levels (PLs) in case of occurrence of properly defined earthquake hazard levels, in terms of annual rate of exceedance λ (or return period TR≈1/λ). Target PLs are properly defined in PERPETUATE guidelines for cultural heritage assets [15], which consider not only the use and safety of people but also the conservation of the architectural and artistic value of the monument. Therefore, target PLs are defined (Figure 1) with reference to three different groups of Safety and Conservation requirements (n=U,B,A): Use and human life (U): also for a cultural heritage asset, similar to ordinary buildings, the possibility of an immediate occupancy after an earthquake and the protection of human life has to be considered; 12 Final Report Building conservation (B): due to the intangible value of a cultural heritage asset, the preservation from building damage is not related, as for ordinary buildings, to the costs of repair or rebuilding but to the possibility of restoration or to collapse prevention, in order to maintain, at least, the monument as a ruin; Artistic assets conservation (A): in many cases, severe damage to artistic assets occurs also in the case of moderate damage to structural elements; therefore, it is necessary to define specific PLs for each relevant artistic asset in the building. PLs are obviously correlated to the seismic response of the structure, which is empirically defined, in macro seismic post-earthquake assessment, by observational Damage Levels (DLs): 1) slight; 2) moderate; 3) heavy; 4) very heavy; 5) collapse. SAFETY AND CONSERVATION REQUIREMENTS - PERFORMANCE LEVELS SEISMIC DEMAND U Targets B Targets A Targets DAMAGE DAMAGE USE and BUILDING ARTISTIC ASSETS LEVEL LEVEL HUMAN LIFE CONSERVATION n =U, B, A GLOBAL SCALE – ARCHITECTONIC ASSET LOCAL SCALE - ARTISTIC ASSET 1 OPERATIONAL NO DAMAGE 1 NEAR INTEGRITY DAMAGED BUT IMMEDIATE DAMAGE WITH LOW 2 OCCUPANCY LIMITATION 2 AESTHETIC 2U IMPACT SEVERELY SIGNIFICANT DAMAGED LIFE SAFETY 3 BUT RESTORABLE 3 BUT STILL 3U DAMAGE RESTORABLE 3B 3A NEAR LOSS 4 COLLAPSE 4 PREVENTION 4B 4A Figure 1: PERPETUATE performance levels, corresponding damage levels and related target return periods (for each target, the primary and secondary PLs are marked in orange and light orange, respectively). Figure 2 summarizes the basic steps of PBA according to the procedure of these guidelines, where the displacement-based approach is adopted as the standard method for vulnerability assessment of cultural heritage and design of preventive interventions. In the following diagram the attention is focused only on the use of static nonlinear analysis (pushover). The pushover curve represents the capacity of the historical building in terms of total base shear versus displacement u of a reference point; DLs are identified on the pushover curve through proper thresholds (in particular a multiscale approach is proposed for complex building, taking into account the damage in single elements, macroelements and at global scale). The seismic demand is defined by the hazard curve, obtained through a Probabilistic Seismic Hazard Analysis (PSHA), which gives the selected Intensity Measure (IM) as a function of the annual probability of occurrence (or the return period). Possible IMs are: peak ground acceleration (PGA), spectral acceleration for a given period, maximum spectral displacement, Arias intensity and Housner intensity [16]. In the standard case of nonlinear static analysis, the seismic demand is represented by an Acceleration- Displacement Response Spectrum (ADRS), which must be completely defined, for the specific site of the building under investigation, as a function of the assumed IM. 13 Final Report POSITIONING OF PLs ON THE PUSHOVER CURVE EVALUATION OF IMPL V Sa η : reduction factor of overdamped spectra IM3B S1 (T) η(T3B,ξ3B) IM3B ⋅ T2A T3B 3B 3A 3B 2A IM2A IM2A S1 (T) η(T2A,ξ2A) u2A u3B EDP=u d2A d3B Sd DEFINITION OF IM & SEISMIC DEMAND PSHA AND VERIFICATION Sa ADRS format IM2A IM3B IM IM = PGA Normalized spectral shape S1 λ2A TR,2A λ2A λ2A λ2A > λ2A ! rehabilitation decision! 1 λ3B TR,3B λ3B λ3B λ3B < λ3B ! PL fullfilled! Sd λ Figure 2: Performance-based assessment of architectural and artistic assets by the PERPETUATE procedure. The outcome of the assessment is IMPL, which is the maximum value of the intensity measure that is compatible with the fulfillment of each target PL: it is directly computed, without any iterative procedure, by the capacity spectrum method with an over damped spectra [17]. Thus, through the hazard curve, it is possible to evaluate the annual rate of exceedance λPL of the earthquake correspondent to this performance (or its return period TR,PL≈1/λPL). These values are compared with the target earthquake T ≈ 1 λ PL hazard levels R ,PL , defined for the assessment as a function of the asset characteristics, in terms of safety and conservation requirements (Figure 1) and properly calibrated through an importance factor γn, in order to take into account the architectonic and artistic value, as well as the condition of use. The acquisition of the best possible knowledge for the definition of the structural model of the building is referred to as: geometry of structural elements; foundations; material properties; historical data on transformation and damage; state of maintenance and damage mechanisms identification (in case of post- earthquake assessment); dynamic behavior. However, in cases of historical masonry buildings it is necessary to consider that the number of investigations should be minimized to reduce the impact on conservation, as well as costs. In order to consider in the assessment the uncertainties due to incomplete knowledge, the common approach adopted by standards for existing structures [10, 11] is based on the definition of a discrete number of Knowledge Levels (KL), achievable as a function of gathered information, and on the application 14 Final Report of a Confidence Factor (CF) to one parameter of the analysis, assumed a priori as the most significant in the assessment. The PERPETUATE procedure has introduced the sensitivity analysis as an essential tool for the seismic assessment of existing and monumental buildings [18], which aims to: - identify the parameters that most affect the structural response, allowing to optimize the investigation plan and strengthen the link between knowledge and assessment; - include explicitly in the methodological path the evaluation of uncertainties, by considering both aleatory (treated as random variables) and epistemic (treated by the logic tree approach) ones, as well as the model error contribution; - select properly (instead of a priori) the parameter for the application of CF and calibrate its value (instead of assuming it conventionally). The use of sensitivity analysis is codified in a well-defined procedure, subdivided into four steps (Figure 3): 1) preliminary knowledge; 2) sensitivity analysis; 3) plan of investigations and execution of tests; 4) evaluation of the CF for the final assessment. PRELIMINARY SENSITIVITY PLAN OF INVESTIGATIONS FINAL KNOWLEDGE ANALYSIS & TESTING ASSESSMENT Phase 1 Phase 2 Phase 3 Phase 4 Basic!knowledge.. For.each.Xk.and.Yj. For.Yj:. 1a Selec0on.of.P.op0ons. Analysis.of.models.with.. 2a .for.pushover.analyses.. 4a Decision.on.KL.to.be. 3a ..Iden0fica0on.of. wm.≠.0.(m=1..M’).and. achieved. .aleatory.(Xk.).and.. combina0on.rules. (KLL,KLM,KLH).. 1b epistemic.. Sensi0vity.analysis.. For.Xk:.. 2b uncertain0es.(Yj). P.M’.(1+2N).analyses. Execu0on.of.tests.&. ASribu0on.of.βXk. postHprocessing.of. .For.Xk.(1..N):. 4b PostHprocessing.. results:. Computa0on.of.the. Ra0onal.range.of. of.results:. CF.value. varia0on.and.mean.value. IMPLi,k,m,p..... .For.Xk.:. 2c ΔPLi,Xk.,..ΔPLi,Yj.. Acceptance.(1c).or. 3b For.Yj.(1..M):. Final.assessment.. upda0ng.of.mean.values. 1c SeGngHup.of.models.. . ASribu0on.of.the. . .Sensi0vity.Class.(SC). ( ) IM PLi ,m = 1 + Δε ,PLi ,m IM PLi ,kCF ,m 4c For.each.combina0on.of. For.Yj:. models.(m=1..M’):. ASribu0on.of.reliability. M' Selec0on.of.the.parameter.. IM PLi = ∑ wm IM PLi ,m Model.error.Δε,PLi,m. degree.(wYj,q). 2d for.the.applica0on.of.CF. m=1 . Rerunning!of!phase!2!in!case!of!significant! update!of!Xk!mean!values! Figure 3: Flowchart of the procedure for planning investigations through the use of sensitivity analysis. Rehabilitation decisions can be assumed thanks to the result of the assessment. Different conservation and preventive strategies can be assumed: a) no intervention, if the building in its actual state is able to fulfill the required PLs; b) interventions are necessary but can be postponed, because the safety is not far from what is expected (in this case it is possible to estimate, from a probabilistic point of view, the time available before the intervention); c) retrofitting interventions, compatible as much as possible with the conservation requests (principle of “minimum intervention”, are necessary now. Whether, in order to fully fulfill the safety requirements, strengthening techniques would be too invasive, it is better to adopt only partial solutions, by postponing further interventions to a future time, when more information on seismic hazard in the region, improved numerical models for the structural analysis and new more effective and less intrusive techniques may be available. In all cases, the implementation of a Structural Health Monitoring 15 Final Report (SHM) system is advisable, in order to detect any change in structural elements and connections and record any future events (micro tremors or low intensity earthquake), with the aim of an updated model for the next safety evaluation. 2.4 Decision-making on strengthening interventions The theoretical, numerical and experimental research developed within the PERPETUATE project has produced exploitable tools and comprehensive procedures for the PBA of cultural heritage assets. The main idea is to consider for historical masonry structures both safety and conservation requirements, by an optimal integration between qualitative and quantitative information. The procedure assumes as essential the use of numerical modeling and nonlinear analysis but makes less mandatory the verification of fixed safety levels; the quantitative assessment of the seismic intensity measure which produces the attainment of the required PLs is necessary anyway, in order to make the procedure repeatable and verifiable. An important feature of the procedure is the use of sensitivity analysis, which permits limiting the number (and consequently the invasiveness) of in-situ (on-site) investigations and testing and, at the same time, optimizing their usefulness for assessment. An original method is proposed for the definition of the Confidence Factor, to be adopted in order to take into account incomplete knowledge; also the estimate of the model error can be implemented in the assessment, which allows the consideration of quantitative data in those cases where the qualitative approach proves the actual safety is higher than that provided by the numerical model (this is useful for limiting invasiveness of strengthening interventions, for the sake of conservation. The application to different case studies has formed the basis for proposing the following guidelines for the seismic assessment and the decision-making on the need of preventive strengthening interventions. The following steps should be followed: 1. QUALITATIVE DIAGNOSIS a. Visual inspection of the building. b. Recognition of crack patterns, static movements, past earthquakes damage. c. Historical analysis (sequence of construction, transformations, interventions). d. Identification of the structural system. à Foresight of the seismic behavior and the specific vulnerability, taking advantage of the comparative seismic damage observation on similar structures or, if present, of minor seismic damage (it is worth noting that in the case of past strong earthquakes, usually buildings are significantly modified, so it is harder to infer seismic behavior) 2. PRELIMINARY KNOWLEDGE AND SENSITIVITY ANALYSIS a. Geometric survey. b. Constructive/structural survey, by visual inspections or non-destructive investigations. c. Few non-destructive or slightly-destructive diagnostic tests on material properties. d. Structural modelling, by one or more approaches (in case of epistemic uncertainties), and definition of plausible ranges for the parameters (aleatory uncertainties). 16 Final Report e. Sensitivity analysis, to the above-mentioned parameters and modelling strategies. à Detection of the most significant parameters to be investigated, in order to improve the reliability of the assessment 3. PLAN INVESTIGATIONS AND DEFINITION OF CONFIDENCE FACTORS a. Selection of the non-destructive or slightly-destructive investigations and diagnostic tests to be performed, in order to improve the knowledge of the most significant parameters, taking also into account the invasiveness and the reliability of each technique. b. Execution of the programme of investigations and updating of mean geometric and material parameters in the structural model. à Evaluation of the Confidence Factor to be used in the assessment 4. PERFORMANCE-BASED ASSESSMENT IN THE CURRENT STATE a. Selection of PLs to be considered for the building, in terms of use and safety of human life, building conservation and artistic assets conservation. b. Probabilistic Seismic Hazard Assessment in the region, with evaluation of seismic input for different return periods. c. Global seismic analysis: 1. Evaluation of the capacity (pushover analysis). 2. Identification of PLs on the pushover curve, by the multiscale approach (in the case of artistic assets that are strictly connected to structural elements, the correspondent PLs are related to specific points of the pushover curve). 3. Evaluation of the seismic intensity measure values which produce the attainment of each PL (IMPL,G). d. Local seismic analyses: 1. Selection of local mechanisms that are worth taking into consideration and are not properly modelled by the global analysis (e.g. out-of-plane of portions of the façade, when the numerical model considers only the in-plane behaviour). 2. Identification of artistic elements that are independent (e.g. a carved stone pinnacle). 3. For each one: evaluation of the seismic demand (floor spectra), of the capacity (with PLs) and of the corresponding intensity measure (IMPL,L). e. Evaluation of the seismic intensity measure values that produce the attainment of each PL (IMPL), by considering the results obtained both at global and local scale. à Evaluation of the annual probability of occurrence of each PL (lPL) and comparison with the corresponding target values 5. DECISION-MAKING ON PREVENTIVE INTERVENTIONS a. The outcome of the PBA is positive ( or ): this means the historical building is able to fulfill all the desired performances, in terms of safety and conservation, and thus no intervention is needed (the installation of a SHM system, or at least a plan of regular inspections, is advisable in order to check whether the present structural conditions remain the same in the future). 17 Final Report b. The seismic safety is not sufficient, even if close to what is required, but it is not possible to intervene with a retrofitting at the moment (due to budget limitations or because the available techniques of intervention would be much too invasive for the conservation of the structure vis-à-vis its cultural value): a limitation of use can be decided (therefore, the importance factor γU changes the target earthquake hazard levels for the fulfilment of Use and human life PLs), as well as some provisional interventions (that have usually the merit of being reversible). A probabilistic justification for postponing the intervention without limiting the use of the building is given by the definition of the nominal life VN of the asset, which is defined as the number of years in which the building can be used and the architectural and artistic assets can be considered preserved from earthquake risk, assuming that it is subject to regular maintenance [14]. Since hazard levels are usually defined by probabilities of exceedance in 50 years, the nominal life is given by: TR ,PL VN ,PL = 50 = 50 I S ,PL (2.1) TR ,PL Thus, it may be assumed that the seismic performance of the architectural asset is adequate if VN,PL>50 years. The nominal life VN,PL is a useful parameter to quantify the time within which preventive actions have to be implemented. This approach is correct if Building conservation (B) and Artistic assets conservation (A) targets of performance are considered, because the accepted safety level refers to a probability of occurrence in a long time window. On the contrary, as far as Use and human life (U) performance levels are concerned, in particular 3U (Life Safety), it is evident that accepted probability of occurrence refers to a short time window (e.g. annual rate of exceedance), because it is related to the presence of people in the buildings. Moreover, it is worth noting that the use of VN,PL is correct from a conceptual point of view only if a time-dependent hazard is available. In the most common case of a Poisson hazard model, the definition of VN,PL represents only a rational approach to accommodate the problem of finding a balance between safety and conservation requirements. c. The historical building is very vulnerable ( or ): seismic retrofitting interventions have to be designed, according to the following sequential steps: i) prevention from local mechanisms (if they are more vulnerable than the global seismic behavior of the building); ii) local interventions on independent artistic assets that are not verified; iii) identification of a global strengthening strategy, according to an approach coherent to the conservation of the cultural heritage, by taking advantage both of qualitative interpretation and numerical results. The PBA procedure is then applied to the retrofitted configuration, in order to evaluate the improved values of IMPL and to compare them with the target values. If the improvement is significant, even if not sufficient to fulfil all the requirements, it is possible to adopt the same approach of the previous point (5b). Also in this case the installation of a SHM system is advisable in order to check whether the structural conditions achieved after the interventions remain the same in the future. à Evaluation of the Confidence Factor to be used in the assessment The use of static nonlinear analysis (pushover), for the evaluation of capacity, is very effective for historical masonry buildings, because it allows for the identification of the causes of vulnerability and the possible alternative strategies of intervention. In particular, the adoption of the displacement-based approach for the seismic assessment helps figure out that in order to reach the required performance it is possible to: 18 Final Report •increase the displacement capacity; •increase the strength; •increase both strength and displacement capacity. Sometimes the first option is not feasible, because if the strength is too low it would be necessary to rely on a very flexible behaviour; however, ductility cannot be increased beyond a certain limit and geometric nonlinearity becomes important. Moreover, the building would be much too vulnerable to low intensity earthquakes, with reference to the damage limitation limit state. Techniques that increase strength are usually associated with significant increase of stiffness and consequent reduction of ductility, which is not necessarily positive in terms of seismic performance. Moreover, in most cases, these techniques are very invasive for the conservation of the cultural value of the building. Usually, the last option is the best and may be obtained through the following interventions: 1) displacement capacity - by improving the connections between structural elements (wall-to-wall, floor-to- wall, roof-to-wall, etc.), without increasing the stiffness of horizontal diaphragms too much; 2) strength capacity - by a light enhancement of the masonry strength, when the quality is below the one related to the application of the traditional rules of art in the area or it has deteriorated over time or because of other environmental/anthropogenic actions. It is worth noting that a global insufficient strength/displacement capacity could be due to an irregular behaviour of the building (torsional effects, presence of a single weak macro element, etc.); the multiscale approach is very effective to single out these problems, which otherwise would be lost with the definition of a s.d.o.f. equivalent system. In these cases, local interventions (i.e. selective strengthening of the weak elements or introduction of new elements for limiting eccentricity) could be very useful. References [1] S. M. Titchen, «On the construction of outstanding universal value: UNESCO’s World Heritage Convention (Convention concerning the Protection of the World Cultural and Natural Heritage, 1972) and the identification and assessment of cultural places for inclusion in the Wo», Australian National University, 1995. [2] ICOMOS Hrsg, «The International Council on Monuments and Sites», Herit. Risk, pp. 6–7, 2015. [3] International Council of Monuments and Sites (ICOMOS), «International Charter for the Conservation and Restoration of Monuments and Sites (The Venice Charter 1964)», Int. Congr. Archit. Tech. Hist. Monum., pp. 1–4, 1964. [4] M. Vecco, «A definition of cultural heritage: From the tangible to the intangible», J. Cult. Herit., vol. 11, n. 3, pp. 321–324, 2010. [5] UNESCO, «Convention Concerning the Protection of the World Cultural and Natural Heritage», Gen. Conf. seventeenth Sess., vol. 1, pp. 135–145, 1972. [6] International Council of Monuments and Sites (ICOMOS), International Charter for the Conservation of Historic Towns and Urban Areas (The Washington Charter). 1987, pp. 1–3. [7] ICOMOS Australia, «The Australian ICOMOS Charter for the Conservation of Places of Cultural Significance», Burra, Australia, 1979. [8] C. Goodwin, G. Tonks, and J. Ingham, «Identifying heritage value in URM buildings», J. Struct. Eng. Soc. New Zeal., vol. 22, n. 2, pp. 16–28, 2009. 19 Final Report [9] ICOMOS/ISCARSAH Committee, «Recommendations for the analysis, conservation and structural restoration of architectural heritage», ICOMOS international committee for analysis and restoration of structures of architectural heritage, 2005. [10] CEN (2005) Eurocode 8 - Design of structures for earthquake resistance. Part 3: Assessment and retrofitting of buildings, Brussels, Belgium. [11] ASCE/SEI 41/06 (2007) Seismic Rehabilitation of Existing Buildings, American Society of Civil Engineers, Reston, VA. [12] ISO 13822, Bases for design of structures – Assessment of existing structures, Second Edition 2010-08-01, ISO International Standard, Switzerland, 2010. [13] CIB 335, Guide for the structural rehabilitation of heritage buildings, CIB Commission W023 – Wall Structures, ISBN 978-90-6363-066-9, 2010. [14] Recommendations P.C.M. 9/2/2011, Seismic assessment and risk mitigation of cultural heritage according to Italian Technical Code for Constructions (NTC 2008). G.U. n. 47 of 26-2-2011, Suppl. Ord. n. 54 (in Italian), 2011. [15] S. Lagomarsino, and S. Cattari, «PERPETUATE guidelines for seismic performance-based assessment of cultural heritage masonry structures», Bulletin Earthquake Engineering, vol. 13, n. 1, pp. 13-47, 2015. [16] J. Douglas, D.M. Seyedi, T. Ulrich, H. Modaressi, E. Foerster, K. Pitilakis, D. Pitilakis, A. Karatzetzou, G. Gazetas, E. Garini, and M. Loli, «Evaluation of seismic hazard for the assessment of historical elements at risk: description of input and selection of intensity measures», Bulletin Earthquake Engineering, vol. 13, n. 1, pp. 49-65, 2015. [17] S. A. Freeman, «The capacity spectrum method as a tool for seismic design», Proc. of 11th European Conference of Earthquake Engineering, Paris, France, 1998. [18] S. Cattari, S. Lagomarsino, V. Bosiljkov, D. D’Ayala D, «Sensitivity analysis for setting up the investigation protocol and defining proper confidence factors», Bulletin of Earthquake Engineering, DOI:10.1007/s10518-014-9648- 3. 20 Final Report 3. A NALYSIS OF OPTIONS FOR REDUCTION OF M ULTI - HAZARD R ISKS IN SELECTED BUILDINGS IN B OHOL 3.1 Introduction In accordance with the requirements of Task 2 of the ToR, this chapter describes the risk reduction measures elaborated for three selected structures: • Dimiao Church, • Alburquerque Church, • Panglao Watchtower. Furthermore, this chapter includes comments and advice on the existing project and related design for the Tagbilaran Capitol. With reference to the three above mentioned buildings, the objective here is to identify two alternative options of consolidation strategies for each of them, aiming to reduce their seimic vulnerability. In situ (on- site) surveys were carried out to collect relevant data about the architectural typology, construction techniques and materials, as well as the crack pattern and existing structural damages (See Annex 3 to this report Analyses Of Options For Reduction Of Multi-Hazard Risks In Bohol - Structural Survey - Damage Survey - Structural Interventions). The critical analysis of the collected data led to the identification of the main causes of the weaknesses detected; consequently, overall strategies of risk reduction have been elabourated and described. Two strengthening alternatives for each of the selected buildings have been developed using both conventional and innovative strengthening techniques or materials, with some considerations on the required technical skills needed to implement such techniques vis-à-vis the national and local capacities, as well as locally available materials. International principles and guidelines on cultural heritage conservation have been used as a reference for the entire assignment, with the purpose of maintaining the authenticity of the heritage buildings. Concerning the Tagbilaran Capitol in Bohol, the objective of the assignment was to provide for some revision and improvement inputs to the existing concept design, with the aim of enhancing the structural efficiency of the retrofitting/strengthening measures and the reconstruction intervention foreseen. 3.2 Dimiao Church 3.2.1 Technical background Architecture and construction techniques Dimiao Church is characterised by a Latin cross plan; the walls are about 130cm thick, and consist of two external leaves built of stone (15cm thick), with an inner core (about 1 meter thick) made of lime mortar and rubble (medium and small-sized). From historic records it is assumed that stone leaves were used both 21 Final Report as formwork for casting the conglomerate, as well as for external wall facing. Such construction techniques involve some structural weaknesses that can be summarised as follows: 1. The considerable wall thickness implies the presence of a large mass which moved during a seismic event, increasing the intensity of the horizontal forces acting on the structures. 2. No evidence has been found of connection through the masonry leaves; consequently, when hit by horizontal actions, external leaves are subjected to compressive forces and, because of the limited thickness, tend to fail and collapse. 3. Stonework composing the external leaves is made of medium size stones (30x45cm) and often perpends appear vertically aligned in successive courses, facilitating the formation of cracks. 4. Weak connections among structural elements, in particular among orthogonal walls, facilitate the detachment and overturning of the façades. 5. Mortar joints are very thin, and possibly they were not properly laid but rather created while pouring the inner mixture within the external stone leaves. Crack pattern The observed crack pattern of Dimiao Church confirms the structural weaknesses identified above: 1. Vertical cracks caused by facades overturning, due to lack of connection among orthogonal walls, and vertically aligned perpends. 2. Failure and collapse of the external stone layer, due to lack of connection among the external leaves and the inner masonry core. 3. Dislodgement and bulging of stonework, due to lack of connection among the external leaves and the inner masonry core. 4. Cracking on flat arch lintels caused by horizontal seismic actions. 5. Diagonal shear cracks caused by horizontal seismic actions. 22 Final Report On site investigation campaign To increase the level of knowledge of the structure, the following on site tests were carried out: • Single and double flat-jack tests, to evaluate the acting stress on the masonry and the ultimate masonry strength; • Sonic tests, that provide qualitative information on the masonry mechanical property when results are cross-checked with those provided by the flat-jacks test; • Laboratory compression test on stone specimens, to evaluate the stones compressive strength; • Laboratory analysis for the chemical characterisation of mortar specimens; • Video-endoscopy tests, to inspect the wall thickness; • Test pits to inspect the foundation; • Drilling resistance measurement on wood structures, to assess integrity and/or level of decay of the wood; • Measurement of the wood moisture content, with the use of a hygrometer, to assess the content of water in the wood. Tests description and results are resumed in Annex 1 to this report (Annex 1. Investigation Campaign). 3.2.2 Retrofitting Options The proposed retrofitting options are presented hereunder, characterised by similar efficiency despite the use of different materials. The interventions are conceived with the aim of reducing the Church’s vulnerability to seismic actions with reference to the following mechanisms: • Facades overturning • Failure of external masonry leaves • Cracking of flat arch lintels • Dislodgement of the external stonework Moreover, interventions to improve the overall behaviour of the structure against seismic horizontal forces are proposed. OPTION 1 (Strategy A) Reinforced Perforations on Masonry (Steel Bars) Description: The work includes the insertion of steel bars in the wall thickness in order to effectively connect the three wall leaves composing the masonry; in this way the masonry behaves as a single unit. Also the stone blocks are individually connected to the core in order to avoid detachments due to compressive loads. The stone blocks are connected to the masonry through steel bolts and nuts. Materials: Stainless steel bars, epoxy resin, bar grouting kit, drilling tips for holes deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: perforations with a drill. Skill: ordinary labourer. 23 Final Report Ring beam (Truss Steel Plates): Description: The work includes the insertion of steel plates, 15 mm thick, along the perimeter of the top of the building, with the purpose of connecting the walls to ensure a box-like behaviour, when the structure is subjected to horizontal forces. The curb is also efficient in countering the facade overturning mechanism. The plates will be connected to the core and to the external wall face with bars inserted in holes injected with epoxy resin, in order to ensure the transfer of loads. Materials: steel plates, steel bars, bolts and nuts, epoxy resin, bars grouting kit, drilling tips for holes deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: perforations with a drill, steel welding. Skill: ordinary labourer. Ring beam (Wood): The intervention on the top of the masonry can also be implemented with the use of wooden beam. Description: The work includes insertion of wooden ring beams, 40x20 cm, along the perimeter of the church top, with the purpose of connecting the walls to ensure a box-like behaviour when the structure is subjected to horizontal forces. The curb is also efficient in countering the facade overturning mechanism. The beams will be connected to the core and to the external wall face with bars inserted in holes injected with epoxy resin, in order to ensure the transfer of loads. Materials: wooden beams, steel bars, bolts and nuts, epoxy resin, bars grouting kit, drilling tips for holes deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: perforations with a drill. Skill: ordinary labourer. Steel-Strands Tie-Rods between the walls of the Nave Description: The work includes insertion of tie rods between the walls of the nave with the aim of preventing the relative distancing between parallel walls; because the span is 17m, 13mm-diameter resistance steel strands are advisable, obtaining a rod weight of 16 kg; therefore the initial tie rod pull needs to be operated in order to limit their bending due to their weight. In addition, to split the tie rod span, a hanging system connected to the roof truss is proposed. The total weight of the tie rod is therefore reduced compared to a traditional steel tie rod. The connection to the masonry is made with steel bar- shaped anchor plates of appropriate size. Materials: steel strands, lime mortar, steel bar-shaped anchor plates, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: drilling with a drill at height, implementation of the chain at height requires scaffolding. Skill: labourer with training for working at a height. Intervention on the wall transepts and on the existing buttresses (insertion of rods in the wall thickness): Description: The works include insertion of rods within the wall in order to hinder the overturning mechanism and the bulging of transept's wall façade. The 20mm diameter steel rods are connected to the 24 Final Report masonry with bar-shaped anchor plates. The works also include insertion of rods within the buttresses in order to connect the stone leaf to the inner core, thus avoiding the stone blocks being dislocated due to compression. The 20mm diameter steel rods are connected to the masonry with bar-shaped anchor plates. Materials: steel rods, lime mortar, bar-shaped anchor plates, drilling tips for perforations deeper than 10m. Availability of materials: the materials are easily available except for the equipment for drilling that must be imported. Material compatibility: the materials are fully compatible with existing masonry. Machining: perforations with a drill at high altitude, installation of the tie-rods at high altitude requires scaffolding. Skill: labourer with training for working at a height. Strengthening of Wood or Stone Lintels and Curved Lintels (Steel Plates) Description: the intervention consists in the insertion of steel plates at the intrados of the flat arches to improve the bending behaviour; moreover, the stones that constitute the external layer around the opening are connected to the core with steel bars to avoid the dislodgement in case of horizontal actions. Materials: steel plates, rods, bolts, steel nuts and washers epoxy resin, bars grouting kit. Availability of materials: the materials are easily available Material compatibility: the materials are fully compatible with existing masonry Machining: perforations with a drill Skill: ordinary labourer. Option 1 estimated cost5 A rough estimate of costs necessary to implement the works foreseen by Option 1 on Diamio Church is included in the table at the next page. The costs only cover the implementation of the proposed risk reduction measures, therefore a coefficient equal to 25% has been applied to consider imprecision of quantity, unit costs, and to partially include construction site costs or other complementary costs. The estimate should be verified and completed during the design phase. 5 Unit costs for each risk reduction measure are also included in par. 4.1.4 - Collection of typical intervention details. 25 Final Report OPTION 2 (Strategy B) Reinforced Perforations On Masonry (GFRP Bars) Description: The work includes insertion of GFRP (glass fiber reinforced polymer) bars in the wall thickness in order to effectively connect the three wall leaves making up the masonry; in this way the masonry behaves as single unit. The resin is used to transfer the loads between rods and stone blocks, creating individual connections and avoiding detachments due to compressive loads. Materials: GFRP bars, epoxy resin, bars grouting kit. Availability: materials have to be imported, but are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: perforations with drill. Skill: ordinary labourer. Ring beam (GFRP strips and GFRP mesh): Description: The work includes insertion of GFRP meshing along the perimeter of the church top, with the purpose of connecting the walls to ensure a box-like behaviour, when the structure is subjected to horizontal forces. The curb is also efficient in countering the facade overturning mechanism. The mesh will be connected to the core and to the external wall face with GFRP bars inserted in perforations injected with epoxy resin, in order to ensure the transfer of loads. Materials: GFRP mesh, GFRP strips, GFRP bars, epoxy resin, bar grouting kit, drilling tips for holes deeper than 1 m. Availability: materials have to be imported, but easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: perforations with a drill. Skill: ordinary labourer. Steel-Strands Tie-rods between the walls of the nave: Description: See option 1 above Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: drilling with a drill at height, implementation of a chain at height requires scaffolding. Skill: labourer with training for working at a height. Intervention on the walls of the transept and on existing buttresses (GFRP wrapping): Description: The interventions include the insertion of GFRP strips between the core and the stone layers of the masonry in order to prevent the over-turning and the bulging of the facades of the transept. Strips are inserted by removing a stone row, positioning the strips and finally placing the stone row in its original position. In addition, the insertion of GFRP strips in the two existing buttresses is also proposed, to confine the masonry and to prevent the dislodgement of stones due to compression loads. The strips have a width of 20cm and are soaked with epoxy resin. Materials: GFRP strips 20cm wide, epoxy resin, GFRP bars Availability: materials have to be imported, but easily obtainable. Compatibility: the materials are fully compatible with existing masonry Tasks: drilling with drill at height, implementation of the strip at height, need scaffolding. Skill: labourer with training for working at a height 26 Final Report Reinforcement of wood or stone lintels and curved lintels (GFRP strips) Description: The works include insertions of GFRP strips to the lintels or flat arches intrados, in order to improve the bending behaviour. Moreover, stones that constitute the external layer around the opening are connected to the masonry core with GFRP bars, to avoid the expulsion in case of horizontal actions. Materials: GFRP strips, GFRP bars, epoxy resin, kit for grouting Availability: materials have to be imported, but easily obtainable. Compatibility: the materials are fully compatible with existing masonry Tasks: perforations with drill Skill: ordinary labourer. Option 2 estimated cost A rough estimate of costs necessary to implement the works foreseen by Option 2 on Diamio Church is included in the table below. The costs only cover the implementation of the proposed risk reduction measures, therefore a coefficient equal to 25% has been applied to consider imprecision of quantity, unit costs, and to partially include construction site costs or other complementary costs. The estimate should be verified and completed during the phase of detail design. Numerical analysis A numerical analysis has been conducted to assess the efficacy of the solutions proposed for preventing the transept façade overturning, consisting in the insertion of tie rods and GFRP (Annex 2. Numerical Analysis of Rehabilitation Options). Drawings A3 size drawings showing the rehabilitation options in some detail are presented in Annex 3 to this report (Annex 3. Analyses Of Options For Reduction Of Multi-Hazard Risks In Bohol - Structural Survey - Damage Survey - Structural Interventions) 27 Final Report 3.2.3 Comparative Analysis From a structural point of view, both options achieve a similar effect; however the strategies differ in other technical and economic aspects. Availability of materials The first strategy involves the use of common materials such as steel bars and readily available steel plates commonly found on the Philippine market, while for the second strategy the use of innovative materials made by nets, strips and bars made of glass fiber is proposed; in this case the materials must most likely be imported. Works Supervision Technical Skills Generally, the works supervisor has to be qualified with technical skills and good knowledge of the final design, along with the intervention and processing techniques to be carried out. The first option is more common and usual amongst Philippine technicians because of the use of well-known materials, whereas the second option calls for specific training in knowledge, use and implementation of new materials. Workmen’s Technical Skills Generally, workmen have to be trained to implement conservation works, in terms of technical skills, risks and hazard knowledge. They should always have suitable protective equipment to assure appropriate safety levels. The first option is more common because of the use of well-known materials, whereas the second one calls for a specific training in knowledge, use and implementation of new materials. Works Duration In most cases the proposed interventions show similar duration of works for both strategies, because, as mentioned above, they differ mainly in materials used. Only in the case of GFRP strips wrapping will the local disassembling and re-assembling of the external cladding be included in order to arrange for the strip. This operation is longer in duration but, as mentioned below, it will have less aesthetical impact. Aesthetic Appreciation Regarding the aesthetic appreciation, it can be noted that strategy 2 has a smaller impact on the existing wall masonry, because the strips are inserted under the stone cladding. GFRP bars are free from bolts and fixing washers instead of steel bars. In the first strategy bolts and fixing washers used for the stone cladding fixing are visible; nevertheless their location is designed in order to minimize the visual effect. Compatibility with Existing Buildings Both strategies are fully compatible with the existing buildings; the proposal includes materials that will not cause any modification in terms of chemical and physical characteristics and are durable. Moreover, in most cases the interventions are reversible. A preliminary cost assessment shows that strategy 2 is more expensive, this is mainly related to the import of materials, indeed in the case of a broader application of these kinds of interventions, the difference in costs will be minimized. The table at the next page shows a comparative outline between the two strategies, referring to the description mentioned above. 28 Final Report A=good, B=intermediate, C=basic Criteria Option 1 Option2 Structural Efficiency A A Materials availability A C Works Supervision Technical Skills B A Workmen Technical Skills B A Processing Works Duration A B Intervention Aesthetic Appreciation C A Compatibility with Existing Buildings A A Intervention Costs A B 3.3 Alburquerque Church 3.3.1 Technical background Architecture and construction techniques Alburquerque Church is characterised by a Latin cross plan; the walls are about 130cm thick and consist of two leaves of stone (15cm thick), with an inner core (about 1 metre thick) made of lime mortar and rubbles (medium and small-sized). From historic records it is assumed that the stone leaves were used both as formwork for casting the conglomerate, as well as the external wall facing. Such construction techniques give rise to some structural weaknesses that can be summarised as follows: 1. The considerable wall thickness implies the presence of a large mass which is moved during a seismic event, increasing the intensity of the horizontal forces acting on the structures. 2. No evidence has been found of connection through the masonry leaves; consequently, when hit by horizontal actions, external leaves are subjected to compressive forces and, because of the limited thickness, tend to fail and collapse. 3. Stonework composing the external leaves is made of medium size stones (30x45cm) and often perpends appear vertically aligned in successive courses, facilitating the formation of cracks. 4. Weak connections among structural elements, in particular among orthogonal walls, facilitate the detachment and overturning of the façades. 5. Mortar joints are very thin, possibly they were not properly laid but rather created while pouring the inner mixture within the external stone leaves. The portico-façade is constituted of a series of masonry arches with a reinforced concrete addition on which the belfry is placed. 29 Final Report Crack pattern The observed crack pattern of Alburqueruqe Church confirms the structural weaknesses identified above: 1. Failure and collapse of the external stone layer, due to lack of connection among the external leaves and the inner masonry core. 2. Dislodgement and bulging of stonework, due to lack of connection among the external leaves and the inner masonry core. 3. Stonework cracking 4. Diffused cracks throughout the masonry portico 5. Cracking on the concrete elements added to the masonry portico-façade. Alburqueque Church did not suffer major damages after the 2013 earthquake, compared with other churches, probably due to the presence of buttresses that have reduced the vulnerability of the entire structure. Many buttresses are damaged, proving that they have effectively absorbed the seismic forces, safeguarding the whole of the structure. On site investigations campaign To increase the level of knowledge of the structure, the following on site tests were carried out: • Single and double flat jacks test, to evaluate the acting stress on the masonry and the ultimate masonry strength; • Sonic tests, that provide qualitative information on the masonry mechanical property when results are cross-checked with those provided by the flat jacks test; • Laboratory compression test on stone specimens, to evaluate the stones compressive strength; • Laboratory analysis for the chemical characterisation of mortar specimens; • Video-endoscopy tests, to inspect the wall thickness; • Ultrasonic and sclerometric tests on concrete elements for the characterisation of mechanical properties; • Test pits to inspect the foundation; 30 Final Report • Drilling resistance measurement on wood structures, to assess integrity and/or level of decay of the wood; • Measurement of the wood moisture content, with the use of a hygrometer, to assess the content of water in the wood. Tests description and results are resumed in Annex 1 of this report (Annex 1. Investigation Campaign). 3.3.2 Retrofitting Options The proposed retrofitting options are presented according to different approaches, characterised by equal efficacy despite the use of different materials. The interventions are designed with the aim of reducing the Church’s vulnerability to seismic actions with reference to the following mechanisms: • Facades overturning • Failure of external masonry leaves • Cracking of flat arch lintels • Dislodgement of the external stonework Moreover, interventions to improve the overall behaviour of the structure against seismic horizontal forces are also proposed. Strategies “A” and “B” proposed for Albuquerque Church walls strengthening are the same as those described for Dimiao Church (see section above: 3.2.2 Dimiao Church - Retrofitting Options) but include interventions on arches and concrete elements as described here below: OPTION 1 (Strategy A) Tie-Rods in correspondence of Arches: Description: The works include insertion of rods in the arches, with the purpose of preventing the relative distancing between piers and eliminating the load due to the constructive structure of the arch. Material: steel rods, lime mortar, steel bar-shaped anchor plates, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: drilling with a drill at height, implementation of the chain at height, requires scaffolding. Skills: labourer with training for working at a height. Intervention on concrete elements (steel plates) Description: The work includes the repairing of damaged concrete elements by using steel plates connected to the concrete element, with steel bars inserted in perforations injected with epoxy resin. The steel plates provide additional strength in the case of a load increase. Materials: steel bars, resin, steel plates, bars grouting kit Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. 31 Final Report Tasks: drilling on concrete elements. Skills: labourer with training for working at a height Intervention on concrete nodes (metal plates) Description: The work includes the repairing of damaged concrete nodes by using steel plates connected to the concrete element, with steel bars inserted in perforations injected with epoxy resin. The steel plates provide additional strength and additional stiffness in the case of a load increase. Materials: steel bars, steel plates, epoxy resin, bars grouting kit Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: drilling on concrete elements. Skills: labourer with training for working at a height. Option 1 estimated cost A rough estimate of costs necessary to implement the works foreseen by Option 1 on Alburquerque Church is included in the table below. The costs only cover the implementation of the proposed risk reduction measures, therefore a coefficient equal to 25% has been applied to consider imprecision of quantity, unit costs, and to partially include construction site costs or other complementary costs. The estimate should be verified and completed during the design phase. OPTION 2 (Strategy B) Tie-Rods in Correspondence of Arches Description: The works include insertion of rods in the arches, with the purpose of preventing the relative distancing between piers and eliminate the load due to the constructive structure of the arch. Material: steel rods, lime mortar, steel bar-shaped anchor plates, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. 32 Final Report Compatibility: materials are fully compatible with existing masonry. Tasks: drilling with a drill at height, implementation of the chain at height, requires scaffolding. Skills: labourer with training for working at a height. Intervention on concrete elements (steel plates) Description: The work includes repairing of damaged concrete elements by using steel plates connected to the concrete element, with steel bars inserted in perforations injected with epoxy resin. The steel plates provide additional strength in the case of a load increase. Materials: steel bars, resin, steel plates, bars grouting kit Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: drilling on concrete elements. Skills: labourer with training for working at a height. Intervention on concrete nodes (metal plates) Description: The work includes the repairing of damaged concrete nodes by using steel plates connected to the concrete element, with steel bars inserted in perforations injected with epoxy resin. The steel plates provide additional strength and additional stiffness in the case of a load increase. Materials: steel bars, steel plates, epoxy resin, bars grouting kit Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: drilling on concrete elements. Skills: labourer with training for working at a height. Numerical analysis A numerical analysis has been conducted to assess the efficacy of the solutions proposed for preventing the transept façade overturning, consisting of the insertion of tie rods and GFRP (Annex 2. Numerical Analysis of Rehabilitation Options). Option 2 estimated cost A rough estimate of costs necessary to implement the works foreseen by Option 2 on Alburquerque Church is included in the table below. The costs only cover the implementation of the proposed risk reduction measures, therefore a coefficient equal to 25% has been applied to consider imprecision of quantity, unit costs, and to partially include construction site costs or other complementary costs. The estimate should be verified and completed during the design phase. 33 Final Report Drawings A3 size drawings showing the rehabilitation options in detail are presented in Annex 3 of this report (Annex 3. Analyses Of Options For Reduction Of Multi-Hazard Risks In Bohol - Structural Survey - Damage Survey - Structural Interventions). 3.3.3 Comparative Analysis From a structural point of view, both options aim to achieve a similar effectiveness; however the strategies differ in other technical and economic aspects. Availability of materials The first strategy involves the use of common materials such as steel bars and readily available steel plates commonly found on the Philippine market, while for the second the use is proposed of innovative materials made by nets, strips and bars made of glass fibre; in this case the materials must most likely be imported. Works Supervision Technical Skills Generally, the works’ supervisor has to be qualified with technical skills and good knowledge of the final design, along with the intervention and processing techniques to be carried out. The first strategy is surely more common and usual amongst Philippines technicians because of the use of well-known materials, whereas the second strategy calls for a specific training in knowledge, use and implementation of new materials. Workmen Technical Skills Generally, workmen have to be trained to implement conservation works, in term of technical skills, risks and hazards knowledge. They shall always have to use suitable protective equipment to assure appropriate safety levels. Also in this case the first strategy is surely more common because of the use of well-known materials, whereas the second one calls for a specific training in knowledge, use and implementation of new materials. Works Duration In most cases the proposed interventions show similar duration of works for both strategies, because, as mentioned above, they differ mainly in materials used. Only in the case of GFRP strips bandage will it be 34 Final Report necessary to include local disassembling and re-assembling of the external cladding in order to arrange for the strip. This operation is longer in duration but, as mentioned below, it will have less aesthetical impact. Aesthetic Appreciation Regarding the aesthetic appreciation, it can be noted that strategy 2 has a smaller impact on the existing wall masonry, because the strips are inserted under the stone cladding. Moreover the GFRP bars are free from bolts and fixing washers contrary to steel bars. In the first strategy, indeed, bolts and fixing washers used for the stone cladding fixing are visible; nevertheless their location is designed in order to minimize the visual effect. Compatibility with Existing Buildings Both strategies are fully compatible with the existing buildings, indeed the proposal includes materials that will not cause any modification in terms of chemical and physical characteristics and are durable, moreover, in most cases the interventions are reversible. A preliminary cost assessment shows that strategy 2 is more expensive, this is mainly related to import of materials, however, in the case of a broader application of this kind of intervention, the difference in costs will be minimized. The table below shows a comparative outline between the two strategies, referring to the description mentioned above. A=good, B=intermediate, C=basic Criteria Option 1 Option2 Structural Efficiency A A Materials availability A C Works Supervision Technical Skills B A Workmen Technical Skills B A Processing Works Duration A B Intervention Aesthetic Appreciation C A Compatibility with Existing Buildings A A Intervention Costs A B 3.4 Panglao Watchtower 3.4.1 Technical background Architecture and construction techniques Panglao Watchtower is characterised by a hexagonal plan; the walls have variable thickness from about 250cm at the base to about 90cm at the top. Walls consist of two external leaves built of stone (15cm thick), with an inner core (about 1 metre thick) made of lime mortar and rubble (medium and small-sized). From historic records is assumed that the stone leaves were used both as formwork for casting the 35 Final Report conglomerate, as well as external wall facing. Such construction technique involves some structural weaknesses that can be summarised as follows: 1. The considerable wall thickness implies the presence of a large mass which is moved during a seismic event, increasing the intensity of the horizontal forces acting on the structures. 2. No evidence has been found of connection through the masonry leaves; consequently, when hit by horizontal forces, external leaves are subjected to compressive forces and, because of the limited thickness, tend to fail and collapse. 3. Stonework composing the external leaves is made of medium size stones (30x45cm) and often perpends appear vertically aligned in successive courses, facilitating the formation of cracks. 4. Weak connections among structural elements, in particular among orthogonal walls, facilitate the detachment and overturning of the façades. 5. Mortar joints are very thin, and possibly they were not properly laid but rather created while pouring the inner mixture within the external stone leaves. 6. Lack of connection through the three masonry leaves favours the dislodgement and failure of stones, particularly at the openings and corners. Crack pattern The observed crack pattern of Panglao Watchtower confirms the structural weaknesses identified above: 1. Failure and collapse of the external stone layer due to lack of connection among the external leaves and the inner masonry core. 2. Dislodgement and bulging of stonework due to lack of connection among the external leaves and the inner masonry core. 3. Stonework cracking. On site investigation campaign To increase the level of knowledge of the structure, the following on site tests were carried out: • Single and double flat jacks test, to evaluate the acting stress on the masonry and the ultimate masonry 36 Final Report strength; • Sonic tests, that provide qualitative information on the masonry mechanical property when results are cross-checked with those provided by the flat jacks test; • Laboratory compression test on stone specimens, to evaluate the stones compressive strength; • Laboratory analysis for the chemical characterisation of mortar specimens; • Video-endoscopy tests, to inspect the wall thickness; • Test pits to inspect the foundation; Tests description and results are resumed in Annex 1 of this report (Annex 1. Investigation Campaign). 3.4.2 Retrofitting Options The two proposed retrofitting options are presented according to different approaches. The first approach maintains the structure as a ruin, implementing only safety measures aimed at reducing the vulnerability to seismic forces with reference to the following mechanisms: • Failure of external masonry leaves • Cracking of flat arch lintels • Dislodgement of the external stonework Moreover, interventions to improve the overall behaviour of the structure against seismic horizontal forces are also proposed. The second approach is based on the existing design concept for the restoration of the tower that foresees: • Insertion of a steel stair structure inside the tower • Reconstruction of the intermediate flooring • Reconstruction of the roof The reconstruction of the existing central wood which carries the stairs is also provided here. Interventions aimed at improving the overall behaviour of the structure against seismic horizontal forces is also proposed. OPTION 1 (Strategy A) Reinforced perforations on masonry (steel bars) Description: The work includes insertion of steel bars in the wall thickness in order to effectively connect the three wall leaves composing the masonry; in this way the masonry behaves as a single unit. The stone blocks, also, are individually connected to the core in order to avoid detachments due to compressive stress. The stone blocks are connected to the masonry through steel bolts and nuts. Materials: Stainless steel bars, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: perforations with a drill Skill: ordinary labourer. 37 Final Report Ring beam (steel plates) Description: The work includes insertion of steel plates, 15mm thick, along the perimeter of the top of the building, with the purpose of connecting the walls to ensure a box-like behaviour, when the structure is subjected to horizontal forces. The ring beam is also efficient in countering the façade overturning mechanism. The plates will be connected to the core and to the external stone leaf with bars inserted in perforations injected with epoxy resin, in order to ensure the transfer of stress. Materials: steel plates, steel bars, bolts and nuts, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: perforations with a drill, steel welding. Skill: ordinary labourer. GFRP wrapping Description: The works include insertion of GFRP strips and 16mm diameter GFRP bars, in structural typologies such as towers and bell towers, with the purpose of encircling the building’s volume so as to obtain a confinement effect, thus improving the compression behaviour. This will hinder the transverse deformation due to the Poisson effect. Materials: GFRP strips, GFRP bars, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials have to be imported, but are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: perforations with a drill. Skill: ordinary labourer. Connection of wall corners with bars in a quincunx pattern (steel bars) Description: The work includes insertion of 14mm diameter steel bars on cornerstones in towers and bell towers, structural typologies in which the edges are the zones most stressed by compression due to horizontal forces; stones not connected to the masonry tend to be dislocated due to instability. Materials: steel bars, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: perforations with a drill. Skill: ordinary labourer Connections in the wall thickness in correspondence of openings (steel bars) Description: The work includes insertion of 14mm diameter steel bars on stone blocks around the openings in towers and bell towers, structural typologies in which horizontal forces such as an earthquake can cause concentrations of stresses with consequent dislocation of stones not connected to the masonry. Materials: steel bars, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: perforations with a drill. Skill: ordinary labourer. 38 Final Report Option 1 estimated cost A rough estimate of costs necessary to implement the works foreseen by Option 1 on Panglao Watchtower is included in the table below. The costs only cover the implementation of the proposed risk reduction measures, therefore a coefficient equal to 25% has been applied to consider imprecision of quantity, unit costs, and to partially include construction site costs or other complementary costs. The estimate should be verified and completed during the design phase. OPTION 2 (Strategy B) Strategy B includes wall strengthening as in strategy A (see above section Strategy “A” proposed solutions) but includes the requalification of the tower as shown in the existing project "Bohol/Guiuan Heritage Site Restoration & Reconstruction (Panglao Watchtower)" by Marvin M. Belgica, Ar. Nelson L. Aquino, Ar. Evelyn I. Esguerra and Jeremy Barns Ceso III; the project consists of the insertion of helical steel stairs and the reconstruction of floors and the roof. We have also provided for the insertion of four wooden pillars to support the stairs and the floors. The stairs are made of steel and is constituted of a single tubular profile with helical development on which the steps made of steel and stainless steel grate are welded. The parapet is made of wood composite baluster and a wood composite handrail. The floors, which are made of wood and consist of beams and planks, are connected to the masonry by steel corbels inserted in the walls and on which the wooden beams of the floor lie. The roof is constituted of a double wood truss on which the secondary beams, the wooden plank and the covering lie. In relation to the existing project, we propose again the original architectural structure where the floors are born by the masonries; this is because the vertical loads stabilise the masonry and increase the shear strength. We also inserted four wood pillars as a support for the wooden beams. Numerical analysis A numerical analysis has been conducted to assess the efficacy of the solutions proposed for preventing the transept façade overturning, consisting in the insertion of tie rods and GFRP (Annex 2. Numerical Analysis of Rehabilitation Options). 39 Final Report Option 2 estimated cost A rough estimate of costs necessary to implement the works foreseen by Option 2 on Panglao Watchtower is included in the table below. The costs only cover the implementation of the proposed risk reduction measures, therefore a coefficient equal to 25% has been applied to consider imprecision of quantity, unit costs, and to partially include construction site costs or other complementary costs. The estimate should be verified and completed during the design phase. Drawings A3 size drawings showing the rehabilitation options in detail are presented in Annex 3 of this report (Annex 3. Analyses Of Options For Reduction Of Multi-Hazard Risks In Bohol - Structural Survey - Damage Survey - Structural Interventions) 3.4.3 Comparative Analysis The two alternative strategies are in this case based on totally different approaches, in as much as the first option foresees the preservation of the monument as it is, i.e. as a ruin, with some retrofitting of the walls to reduce their seismic vulnerability. The second option foresees the restoration of the monument, following the indications of existing design ("Restoration of Panglao Watchtower"), strengthening the walls, reconstructing the intermediate ceilings with wood, rebuilding the internal stairs with a steel structure and a new wooden roofing structure. Construction materials The first option requires easily available materials such as steel bars and plates, and some innovative materials such as GFRP bars and tapes for the wall strengthening. The second option foresees substantially the same materials with some additional works to rebuild the stairs, the roof and the wooden ceiling, all available on the local market. Skills required for works supervision Previous experience in conservation and restoration works. Required Labour skills Similar for both options, skills in restoration works are requested. 40 Final Report Works duration Option 2 requires a much longer duration. Impact Option 2 will open the structure to internal visits and fruition, while in option 1 the ruin is just an object to be looked at. Compatibility Both options are compatible with the site’s heritage status. Costs Higher in option 2. 41 Final Report 3.5 Recommendations on interventions already designed for the Tagbilaran Capitol The Capitol building in Tagbilaran houses the town hall. Its public use implies a medium-high level of exposure, due to the volume of people present on a daily basis. It should also be considered as a strategic building, whose functionality must always be guaranteed especially in the presence of seismic forces. The original structure, erected in the second half of the XIX century (1852-54) during the Spanish colonial period, was built with the local traditional, construction technique, the typical masonry composed by two external stone leaves about 15 cm thick, with an inner core of mortar and rubble, about 80 cm thick. During the American colonial period and after World War II, reinforced concrete additions were made to consolidate the wall structure; some concrete columns and beams were added in that period, enclosing the existing masonry ones, to form an additional frame supporting the upper floor loads. Furthermore, the new internal non-bearing walls, which were originally made entirely of wood, were rebuilt in reinforced concrete. A site visit was carried out during the week of the 5 - 12 March 2016, aimed at structural survey, structural damages and materials mapping, in particular: • Existing structural elements (walls, columns, floors, roofs) • Masonry cracks • Cracks in reinforced concrete elements • Structural weaknesses Afterwards, the project compiled by Arch. Roldan C. Laurel and Ing. Karlo B. Quiobe ("Restoration & Conversion Of Bohol Capitol To Nm-Tagbilaran & Associated Improvement Of Tagbilaran Plaza") was studied and analysed, with specific reference to international recommendations of Restoration Charts such as ICOMOS ISARCH. Construction details have also been analysed and reviewed in order to optimize their effectiveness. 3.5.1 Structural survey and crack pattern The building presents different construction techniques (different construction phases): Ø masonry consisting of two external stone leaves with the interposition of an inner core of mortar and small and medium sized stone. Several weaknesses have been observed: • Very thick joints decrease the mechanical properties of the masonry • Stonework composed similar to cladding, or a formwork, laying stones with a vertical orientation in coursed rows, and often perpends appear vertically aligned in successive courses. • Lack of transversal connection in the wall thickness • Inner core materials are friable and subject to heavy pulverisation and crumbling phenomena. 42 Final Report Picture 1. Masonry walls, Tagbilaran Capitol Ø reinforced concrete the concrete mixture shows poor mechanical quality, and this is reflected in the numerous cracks present mainly due to localised loads; the steel bars used as reinforcement are smooth and round and often this does not ensure the necessary adherence for properly transmitting the loads. Picture 2. From left: Frames made of reinforced concrete; detail of reinforcement bars Ø steel the vertical steel elements are often characterised by slender sections that are vulnerable to combined vertical and horizontal forces; connecting rods, absorbing horizontal forces between the columns, are also absent. 43 Final Report Picture 3. Steel columns: connecting rods elements are absent. Ø wood wooden structures appear in good condition and no damage related to seismic fores has been observed. In some cases, connections are made by simple contrast and friction, without the presence of nails or steel connectors; this can decrease the functionality of the connection with respect to the horizontal forces. The wooden floors generally have a double frame with planks; the primary frame is formed by almost squared section main beams, while the secondary one is formed by elongated rectangular section beams resting on the short side, with transverse connection between them to avoid twisting; the plank rests above the secondary frame. Such construction technique provides the structure with good stiffness, improving its behaviour when subjected to horizontal forces. The roof is built of wooden trusses and secondary beams, while the roof covering consists of thin metal sheet; consequently, the coverage is characterised by a very low weight, minimizing the inertial mass (at height) heavily affected by earthquakes. The damage observed here is mostly due to moisture. Pictures 5 and 6 show plans of ground floor and first floor, drafted after the survey; in particular: • structural elements (walls, columns, slabs) • type of cracks observed • point of view of selected photos. 44 Final Report Picture 4. From left: wooden slab, wooden cover. Picture 5. cracking pattern, ground floor 45 Final Report Picture 6. cracking pattern, ground floor Picture 7. KEY, cracking pattern. 46 Final Report Picture 8 shows the foundation reaching a depth of about 65 cm, as already observed in other structures. Below the floor level, masonry continues for about two rows; underneath is one layer, which looks similar to the inner core, which constitutes the support at ground level. The soil is usually made up of sand and silt and has cavities in some cases, which can cause sagging in foundations and thus instability of the structures in elevation. Picture 8. Foundation Pictures 5 and 6 show that most of the masonry is cracked, as well as the concrete elements. Pictures 9 and 10 show the portico with a focus on the masonry columns, cracked because of cornerstone failure, and the reinforced concrete columns which have cracks on the outer face. Picture 10 shows an arch where cracks on keystones and voussoirs are clearly visible, likely to activate a failure mechanism. These instabilities can be generally halted with the insertion of steel rods whose task is to absorb the horizontal thrusts of the arches. Picture 11 shows a reinforced concrete column in which the stone coating was probably detached due to alternate horizontal thrusts, and a wooden column in which the attachment node is similar to a hinge which makes the system very vulnerable to horizontal thrusts caused by an earthquake. The final picture shows a steel column, which presents the same problems as the wooden one, being slender and without the presence of bracing systems. Picture 12 shows examples of masonry flat arches; on the right, a detachment of the area above the lintel which denotes the absence of connection to the upper wall. 47 Final Report Picture 9. From left: cracks due to compression on a masonry column, detail, r.c. column encircling the masonry one Picture 10. From left: cracked arch, details of cracking. Picture 11. From left: reinforced concrete column spalling and crushing, detail of wooden column's foot, steel column. 48 Final Report Picture 12. Details of lintels. Picture 13 shows a reinforced concrete portal, set against the existing walls; to the right, a section where cracks, probably caused by the action of horizontal forces, are visible. Picture 13 from left: reinforced concrete portal; detail of cracks probably caused by horizontal forces Picture 14 shows a section of the roof, formed as mentioned, by a wooden, secondary framework and metal steel sheet. The wooden elements appear to be in fairly good condition, namely capable of fulfilling the static function for which they were designed; the connections could be improved, which in some cases were built for contrast and friction between the elements, but it would be more appropriate to include steel elements to ensure a better connection of transfer efforts. 49 Final Report Picture 13. Details of covering. 3.5.2 Description of existing project The project for the Capitol in Bohol involves the construction of a new steel frame, located within the existing structure with a construction joint larger than 10cm, designed to support the intermediate flooring and the roofing structure, made of straight and curved new steel beams. The proposed solution does not involve the consolidation of existing structures, which are considered not appropriate to fulfil static functions. The steel pillars lean on new concrete foundations consisting of slabs, plinths and small walls. The floor beams are constituted by "double T" shaped steel elements, while existing timber flooring is kept; finally, existing roofing structures are replaced with straight and curved steel trusses connected to the new steel columns. Picture 16 shows the design plan for the new foundations, where new slabs adhering to the original masonry are foreseen for connecting the steel columns; no connection between the foundation elements is visible, although, according to many European norms, they significantly improve the structures behaviour when subjected to horizontal forces. In this regard, a reinforced concrete curb, connecting isolated foundation elements, and thus forming a grid of beams, strengthens the foundation, and improves the distribution of tensions on the ground. Picture 17 shows the new design for the second level, with new flooring beams and some shear walls. Steel beams have "double T" sections and are characterised by large spans, being in some cases larger than 10 meters; this may cause problems in terms of torsional flexion instability that must be adequately solved through the introduction of stiffening plates along the axis of the beam. Shear walls are 15 cm thick and are inserted in some cases adhering to the old masonries; their positioning does not look symmetrical with respect to the structure, having also inadequate foundations as they are made of poorly armed foundation curbs. Figure 18 shows the plan of the garret made of wood with a two coplanar frames, built using the traditional Filipino construction technique. Figure 19 shows the roof plan where the existing wooden truss structure is replaced with new steel straight and curved trusses placed on the new steel pillars. 50 Final Report Picture 14. Tagbilaran Capitol: new foundation design. 51 Final Report Picture 15. Capitol in Bohol: second floor framing plan 52 Final Report Picture 16. Capitol in Bohol: Roof framing plan 53 Final Report Picture 17. Capitol in Bohol: trusses and purlins framing plan The approach guiding the structural design, involving the replacement of existing roofing structures, is probably due to the significant level of damage detected: the walls are diffusely cracked due to compression, and concrete elements show cracks due to compression or shear. Consequently, the solution of locally repairing the existing structure, avoiding major consolidation but transferring loads to a new system designed according to updated earthquake engineering regulations, can be shared. With reference to internationally accepted conservation theories, including some of the international restoration charters (such as ICOMOS ISARCH), the solution of replacing existing wooden trusses with new metal structures cannot be equally shared. These elements testify to the traditional Filipino construction technique, and, in addition, generally appear in good condition. An alternative design approach would be to maintain the existing roof, eliminating main vulnerabilities such as improving connections between the wooden elements, realised by simple friction or adherence in the as-built structures. This type of union presents significant vulnerability against horizontal forces, because 54 Final Report this can lead to the separation of the wood elements causing instability or roof collapse; to avoid such failure, metal connectors should be introduced to make connections effective and transfer shear stress. Foundation works require special attention for the presence of possible cavities in the soil beneath the building, as pointed out in the related technical report; the presence of cavities can cause sagging in foundations that usually creates instability to the whole building. It is therefore important to further investigate and determine the actual presence of cavities and, in such cases, provide for an intervention at foundation level with micropiles, in order to transfer the load from the above structure onto a suitable soil level. 3.5.3 Structural improvements to the existing design The following pages describe some proposed improvements to the construction details of the existing structural intervention design. Detail A 55 Final Report DETAIL AS PER EXISTING DESIGN IMPROVED DETAIL IDENTIFIED ISSUES PROPOSED IMPROVEMENTS Two solutions with different purposes are suggested: Curbs, lacking connections to the structure, may not 1) Foundation enlargement: two curbs are efficiently collaborate. proposed alongside the existing masonry, connected with reinforced concrete stringers. Such The curb is simply placed on the ground and intervention is aimed at extending the foundation therefore works as a deadweight to the bars base to obtain a better distribution of tensions on anchored in the curb. This type of connection is the ground. insufficient. The binding of walls with steel wire (reinforced 2) Reinforced plaster: wall binding is realised with plaster) is obtained with a 15 cm thick plaster layer, two reinforced counter walls (10 cm maximum which is overabundant for the static purposes it has thickness) in order to increase the overall wall been designed for. section and improve mechanical characteristics, as the introduction of steel bars also gives the element From the drawings this detail seems to be referred the ability to resist tensile stresses. The reinforcing to shear walls. bars are anchored to the existing masonry, which, being compressed ensures a good anchoring of the bar. 56 Final Report Detail CF1-CF2-CF3 This detail refers to the foundation node, composed of a 300 mm height reinforced concrete slab, and a 900mm tall column of 345x500mm section, on which the pillar is anchored with a steel plate and six anchor bolts. 57 Final Report DETAIL AS PER EXISTING DESIGN IMPROVED DETAIL IMPROVED DETAIL DETAIL AS PER EXISTING DESIGN 58 Final Report DETAIL AS PER EXISTING DESIGN IMPROVED DETAIL IDENTIFIED ISSUES PROPOSED IMPROVEMENTS The slab is armed only at the bottom, with It is advisable to provide the slab with a double bars that have a limited length of anchor cross reinforcement, in its lower and upper parts, bending the bars for a length equal to at least 8 diameters The reinforcement of the slab is placed in a It is advisable to thicken the slab reinforcement uniform manner in the vicinity of the support of the column, where a higher concentration of tensions is present The bolts have only a slight tilt It is appropriate to "U" fold the bars of the bolt to ensure efficiency against traction of the bar, avoiding punching shear effect on the concrete The column is welded to the plate without To create a rigid connection it is advisable to stiffeners introduce stiffening plates that optimizes the transfer of forces caused by bending moments 59 Final Report Detail CS4 The detail refers to the reinforcement of foundation slabs, which are 10cm thick DETAIL AS PER EXISTING DESIGN IMPROVED DETAIL IDENTIFIED ISSUES PROPOSED IMPROVEMENTS The slab is reinforced only on the upper side It is appropriate to equip the slab with a double cross reinforcement, on the upper and lower side; along the outer sides an additional reinforcement, aimed at confining the slab’s edges, may be foreseen Detail CF7-CF8 The detail refers to the connection of a circular steel profile on a concrete partition wall. DETAIL AS PER EXISTING DESIGN IMPROVED DETAIL IDENTIFIED ISSUED IMPROVED DETAILS According to the drawings, the concrete is not It is proposed to insert a specific reinforcement into reinforced the concrete wall and the foundation slab, using a double layer of reinforcing bars in order to absorb 60 Final Report reverse stress. It is also recommended to increase the number of bars of reinforcement in the presence of concentrated loads, in this case in the vicinity of the steel profile. Typical connection detail 1: beam to column The detail refers to the connection of the beam to the column, where the continuity bond is restored DETAIL AS PER EXISTING DESIGN IMPROVED DETAIL IDENTIFIED ISSUES IMPROVED DETAIL The connection, meant to be a rigid one, does not To ensure adequate rigidity of the node, it is have enough rigidity proposed to insert metal plates in the column in the vicinity of the union. 61 Final Report Typical connection detail 2: beam to column The detail refers to the connection of the beam to the column, where the continuity bond is restored IMPROVED DETAIL DETAIL AS PER EXISTING DESIGN IDENTIFIED ISSUES PROPOSED IMPROVEMENTS The connection, meant to be a rigid one, does not To ensure adequate rigidity of the node, it is have enough rigidity proposed to insert metal plates in the column in the vicinity of the union. 62 Final Report Masonry structures With reference to the Capitol existing masonry structures, no specific intervention is analysed by the structural design. One of the reports ("BoholProvincialCapitol_December4") illustrates some typologies of intervention, without providing detailed design and dimensions. Figure 4 below (images are taken from par. 3 and 4 of the mentioned report) illustrates intervention of reinforced perforation aimed at re-establishing physical continuity between damaged structures. In particular, on the left, the perforations are meant to repair cracks in a structural elements, while on the right, bars are finalised at connecting arches and flat arched stone units to the above masonry. Both interventions are effective, and in particular the second one contributes to avoid stone dislodgement frequently observed among the priority structures upon openings (Figure 5). Figure 4. Reinforced perforations Figure 5. Dislodgement of flat arch stone units Figure Figure 6. Repair/reconstruction of an opening Although effective, the proposed interventions are not detailed nor resulting from calculations. Even if, according to the new design, the masonry structures will not play a crucial role for the transferring of loads, due to the presence of new steel structures, specific interventions on masonry should be part of the detailed structural design, to guarantee an appropriate safety level in case of further seismic events, thus avoiding failure and collapse. 63 Final Report During the site visits carried out in the course of this project, some repairs have been observed. Figure 6 shows the repair/reconstruction of a masonry opening, although such intervention is not foreseen or described in the structural design reports. Engineering standards requires that all the foreseen works are planned, drawn up and calculated. Some further intervention suggested for repairing and reducing risks on the Capitol masonry structures are reported below (see also par. 4.1.4 of this report for a detailed description of the intervention). Cracks stapling (C1) The work includes the repair of the crack with fiber-reinforced lime mortar in order to restore the masonry continuity and the insertion of "U" shaped steel rods in order to stop the progression of the crack. Compared to the proposed one, stone units are connected also externally through the U-shaped rods, and, internally, the crack is filled with mortar. Tie-rods in correspondence arches The works include insertion of rods in the arches, with the purpose of preventing the relative distancing between piers and eliminate the load due to the constructive structure of the arch. The use of tie-rods is very effective as they absorb the horizontal stress that frequently causes dislodgement of stone units as well as the arch’s failure. Strengthening of stone or wood lintels and curved lintels (steel plates, M1) The works include insertions of steel plates to the lintels or flat arches intrados, in order to improve the bending behaviour. Ring beam (truss steel plates, Q2) The work includes insertion of steel plates, 15mm thick, along the perimeter of the top of the building, with the purpose of connecting the walls to ensure a box-like behaviour, when the structure is subjected to horizontal forces. The ring beam is also efficient in countering the façade’s overturning mechanism. The plates will be connected to the core and to the external stone leaf with bars inserted in perforations injected with epoxy resin, in order to ensure the transfer of stress. Flooring structures reconstruction (double wood planks, U2) The work is proposed in case the construction of a new wooden floor is required; employing the traditional construction technique of the Philippine intermediate flooring, the aim is to improve the quality of the support for the wooden beam on the wall. It is suggested to create due support with new stones, allowing a better distribution of compressive loads on the masonry and using connectors to ensure the transfer of horizontal forces to the walls. In case of spans higher than 4 meters, it is recommended to realize a double wooden plank, with the aim of stiffening the floor and to allow a better distribution of horizontal forces to the walls. The double planking stiffens the flooring enhancing the transfer of horizontal actions. 64 Final Report Part of the conducted photographic survey is reported in the following pages. The pictures’ codes make reference to the numbered points of view included into the plans. Picture 20 Cracking pattern, ground floor. 65 Final Report Picture 21. Cracking pattern, first floor. Picture 22. Key, Cracking pattern 66 Final Report Photographs 20 and 21 Photographs 31 and 38 Photographs 37 and 39 67 Final Report Photographs 45 and 51 Photographs 46 and 47 Photographs 58 and 55 68 Final Report 4. R ECOMMENDATIONS FOR I MMEDIATE AND M EDIUM -T ERM R ISK R EDUCTION M EASURES FOR P RIORITY S TRUCTURES 4.1 General Concepts 4.1.1 Summary of the Priority Structures Analysed A summary of the priority structures analysed is presented in the table on the next page. 4.1.2 Summary of main weaknesses found in the 16 Priority structures The majority of the observed structures are built of multi-leaves unreinforced masonry, typically realised of facing dressed coral stone or limestone, and a rubble infill of debris and rocks. Main roofing systems are usually constituted of timber trusses and purlins supporting cladding made generally of sheet metal roofing and more rarely of the original ceramic tiles. Often the trusses also support a system of false ceilings made of either timber plank or metal sheeting. Multi-leaves masonry is commonly found in historic structures; in principle, the structural system, based on unreinforced masonry and wood roof trusses, is highly vulnerable to dynamic actions, in particular when connections between elements are not carefully realised. Good connections among vertical and horizontal structural elements ensure the so-called box behaviour: this, providing the transfer of inertial and dynamic actions from elements working in flexure out-of-plane to elements working in in-plane shear, leads to a global response best suited to the strength capacity of the constitutive materials, and hence enhanced performance and lower damage level. With reference to the 16 buildings analysed, recurrent weaknesses have been observed and are described in the following pages. 69 Final Report Total Area Earthquake Wind N° Building Typology Value Use (m²) Vulnerability Risk Vulnerability Risk 1 San Agustin Church Church 2.126 Church High Medium - High High Outstanding architectural Low 2 Convent and historical significance Repository for High Medium - High High San Agustin Convent 8.178 religious High artifacts 3 Baluarte de San Diego Forts 10.880 Touristic n/a n/a n/a n/a High historical significance 4 Manila Metropolitan XX century 10.404 High architectural, None - - n/a n/a Theatre public buildings aesthetic and social significance 5 St. Monica Church - Church Church Medium-High Medium Medium Medium Alburquerque Church 1.983 Historical and architectural 6 St. Monica Church - Convent significance Convent Medium Medium - Medium Medium Alburquerque Convent 1.998 Low 7 Santo Nino Parish Church Church Medium Medium- Low Low Church (Cortez) 1.296 High 8 Santo Nino Parish Bell towers High architectural, Church’s Bell Medium Medium Medium Medium Belltower (Cortez) 195 aesthetic and historical Tower significance 9 Santo Nino Parish Convent School Medium Medium Medium-High Medium- Convent (Cortez) 852 High 10 St. Nicholas Tolentine Church Church Medium-High Medium Low Low 1.762 Parish - Dimiao Church Architectural and historical 11 St. Nicholas Tolentine Convent School Medium Low Medium-High Medium- significance Parish - Dimiao 1.438 High Convent 12 Church 2.044 High architectural, Church Medium-High High Medium-High Medium- Saint Peter the Apostle aesthetic, historical and High 70 Final Report Parish - Loboc Church social significance 13 Loboc Mortuary Chapel Church - Other Medium Medium Low Low 14 Loboc Watchtower Watchtowers 76 None High High Low Low 15 St. Augustine Parish - Church Church Medium Low Low Low 1.431 Panglao Church Historical significance 16 St. Augustine Parish - Watchtowers None Medium Medium- Low Low 401 High architectural and Panglao Watchtower High historical significance 17 Punta Cruz Watchtowers None High Medium- Medium Medium 94 High historical and Watchtower High architectural significance 71 Final Report Texture and nature of the masonry The quality of the masonry depends on its texture (horizontal courses, vertical mortar joints not-aligned, dimensions and shape of the stones, mortar quantity, presence of leaves connections and headers) as much as in the physical, chemical and mechanical characteristics of the components (stone, mortar, rouble infill). The faced stone surface constitutes a peculiar feature of vertical structures; stonework is composed similar to cladding, or formwork, laying stones with a vertical orientation in coursed rows, and often perpends appear vertically aligned in successive courses. In the case of the 16 buildings analysed, the exterior leaves are quite thin and no evidence of transversal connection between the wall leaves has been detected. The inner core is usually constituted of a mixture of lime, debris and rocks, and it often appears friable with limited solidity and strength, as also confirmed by the onsite tests carried out6. As a consequence, the following damages have been frequently observed: • Inner core materials are friable and subject to heavy pulverisation and crumbling phenomena. • Detachment, dislodgement and crashing of the outer stonework layer is very diffuse. • The coral stone masonry is diffusedly cracked. Reinforced concrete additions Reinforced concrete insertion, dating back to the American period, onto Spanish-period religious buildings is very frequent. The addition of concrete structural elements to the unreinforced masonry structure creates problems in terms of nonhomogenous mechanical properties, stiffness and diverse response to dynamic actions. Such uneven structural composition may severely affect the buildings’ performance against dynamic external actions, because of the different behaviours and of the increase of masses applied on the stone masonry. Furthermore, it has been observed that the concrete mixture is of poor quality, with a considerable amount of pebble of noticeable size used as aggregate, and little, as well as, uneven steel reinforcement bars employed (in terms of both threading and dimensions). As a consequence, the reinforced concrete structures appear decayed and damaged, water and humidity being relevant factors as well as earthquakes. The structures appear cracked and spalled, with frequent corrosion of the exposed steel reinforcements. Lack of connections among structural elements When connections between vertical elements, and between vertical and horizontal elements, as well as vaults and domes have sufficient capacity, vertical and horizontal loads are better distributed, out-of-plane mechanisms of damage are prevented and, hence, failure of floors and roofs can be avoided, substantially reducing the probability of collapse and fatalities in an earthquake. On the contrary, weak connections severely affect the buildings’ performance against dynamic external actions, because of the lack of anchors that would prevent disconnection of elements and their collapse. In church-like structures with large span unrestrained walls often the connections at the edges are not sufficient to ensure out of plane stability. This is implicitly recognised in many architectural forms, which include buttresses or chapel partition walls along the lateral walls. These have been encountered in many of the priority structures surveyed. However, notwithstanding their presence their effectiveness might not always be evident in the resulting damage pattern which has affected that specific building. 6 See Annex 1 72 Final Report Weaknesses have been detected in corner stonework, not adequately reinforced, and in the connection of different structural elements. Limited connections among structural elements severely affect the buildings’ performance against dynamic external actions. However, it has often been observed that the presence of buttresses, together with the employment of roof tie trusses, confers some additional resilience to the building concept, although poorly realised. The seismic vulnerability assessment carried out, as well as the onsite observation of damages caused by the 2013 earthquake, demonstrate that weak connections represent a major issue for the Philippines historic built heritage. The main failure mechanism identified is the out-of-plane mechanism/overturning of walls, due to lack of anchorage and the absence of diaphragms, extensively visible in all the analysed buildings; Roof failure Roof failure has been found limited to the cases of the collapse of supporting walls. Generally, intermediate flooring and roofing structures have been found in an acceptable state. Rather than structural failure, decay phenomena has been observed due to lack of maintenance, aging, and the effects of insects and weathering. Indeed, in high wind areas, it is critical to understand the impact high wind forces can have on a roof system, and the preventative fastening techniques essential to maintaining a safe and long-lasting roof system. As the wind flows over a roof, the sheathing on the roof is subjected to aerodynamic forces. Depending on the shape, height, and location of the roof, these forces can act to hold the roof sheathing on or to pull it off of the roof framing. In addition to that, the speed of the wind acts in conjunction with shape, height and location of the roof to determine the magnitude of these forces and their direction, either into the roof – holding the roof on – or away from the roof – pulling the roof off. It is essential to ensure that those forces trying to pull the roof sheathing off are counteracted by sufficient fasteners holding the roof down to the framing. Priority structures observed are generally provided with only a limited number of fasteners, often heavily corroded due to decay phenomena mentioned above. Therefore, the number and state of conservation of such fasteners constitute a weak element of the roof against high wind events. Timber vertical structures Among the priority structures considered, convents and heritage houses are mostly composed of a wooden frame bearing structure; the ground floor is commonly enclosed in masonry casing. Generally such structures are characterised by a better response to dynamic actions than unreinforced masonry, due to the different physical properties of timber materials. However, two main weaknesses have been identified and shall be considered. • A very common issue concerns the widespread decay of structural elements due lack of maintenance, aging, weathering and the attack of termites, which in many cases resulted in a considerable reduction of the structural elements’ resistant section. • With reference to interior partitions, these are realised with a variety of techniques employing wood and lathing. Among these, the old and traditional technique of tabique pampango (wattle and daub) underwent cases of collapse, probably because of the poor quality as well as aging of the mixture used to daub the wattle. 73 Final Report 4.1.3 Notes on risk reduction strategies for main heritage structures in the Philippines Each intervention should be treated according to a clear and specific protocol so as to reach a comprehensive knowledge of each building on different aspects (historical, geometric, architectural, structural etc.). This protocol has been defined as the “knowledge path” by Italian legislation, which is the result of long-standing experience in architectural restoration. Knowledge of the historical masonry building is a basic condition not only for a reliable evaluation of current seismic safety condition, but also for the right choice of an effective intervention of seismic improvement. […] Knowledge may be achieved through different types of in-depth analysis, depending on the accuracy of surveys, historical researches and experimental surveys. […] introduction of: different levels of knowledge with increasing level of in-depth analysis; different “confidence factors” linked to levels of knowledge and to be used both during the analysis of the current situation and after the potential interventions7. The steps of a “knowledge path” are summarised as follows: A: Knowledge 1. identification of the building 2. functional characterization of the building 3. geometrical and structural survey of the current status of the building 4. historical analysis of events and interventions affecting the building 5. survey of construction materials and conservation status 6. mechanical characterization of materials 7. geotechnical aspects 8. monitoring B: Diagnosis C. analysis of the interventions The knowledge path is structured as follows: Identification of the building: identification of the structural unit and localization of elements subject to damage; functional characterization of the building: understanding the causes of structural and geometrical modifications that have occurred, describing the signs and other information regarding the instabilities geometrical and structural survey of the current status of the building: understanding the analysis of the building and the potential adjacent buildings. In this step the following will be defined: the analysis of planimetric and altimetric characteristics of building elements; identification of constraints and loads; 7 Guidelines for the assessment and reduction of seismic risk of cultural heritage according to the updated technical standards for constructions (Ministerial decree 14 January 2008), Chapter 4 “knowledge of the building”; 4.1 knowledge-pat; 4.1.1 general information 74 Final Report information about inaccessible spaces; survey and representation of crack-pattern and/or possible damaging mechanisms; identification of structural elements; historical analysis of events and interventions affecting the building: underlining the different portions of the building in order to identify the possible zones of discontinuity and nonhomogeneity; identifying the structural and/or geometrical modifications of the building as well as the previous uses of the building; defining and localizing the interventions carried out previously and their effectiveness; preparing/organizing documentary research (written and iconographic sources); survey of construction materials and conservation status: acquisition of hidden information through direct and indirect surveys; it is necessary to prepare a plan of the surveys to be carried out; it is also necessary to consider the quality of the masonry according to the local context and the historical period. Moreover it is necessary to read/understand the structural scheme of the building and the characteristics of interconnection of the different elements; mechanical characterization of materials: this analysis provides the parameters of deformability and resistance of the material to be used for modelling. The direct measurement of mechanical parameters can be carried out by destructive or non-destructive tests. Non-destructive tests can be used to assess whether the parameters are homogeneous or not. geotechnical aspects: identification of type and consistency of the foundation system and geotechnical characterization. All the surveys should be carried out only after the analysis of available documentation regarding the historical records of the building has been done. The surveys should allow for the physical and mechanical characterization of the foundation soil by tests in situ or laboratory tests and should provide information about the local seismic responses and the dynamic interaction between the ground and the structure. It is also necessary to include analysis of slope stability and terrain liquefaction. monitoring: it is a periodic control and it is the main tool to preserve the building and to plan the maintenance interventions. For the elaboration of the Monitoring plan, it is necessary to have a preliminary interpretation of the instability mechanism. By monitoring some parameters of the dynamic response, it is possible to identify some potential elements that represent any modification occurred in the building. The choice of the parameters and the interpretation of the dynamic measures should be justified in relation to the typology of instability and to the scope of the surveys. The building knowledge path and diagnosis ends with the determination of needed priority actions. These, should be defined and evaluated depending on the building’s state of damage, or on the results of expeditious assessment methods (e.g. FAMIVE, taking into account the reliability of the results) and considering the level of priority required for their implementation (urgent, medium and long term actions). Critical factors in defining the seismic safety level required for each structure, and the consequent level of priority for the foreseen action, are the following: • Building Usage • Building Dimension • Maximum Number of occupants • Historical and /or Cultural value of the building Intervention strategies can be categorized according to the construction type and typical building construction systems. A brief general analysis of issues identified in Philippine architecture and building typologies is resumed here below. 75 Final Report • Towers Description: Vertical masonry structures with polygonal cross-section and high thickness of the wall at the base decreasing along the height; Vulnerable elements to horizontal actions: Corner and flat arch lintels; Typical failure mechanism: Overturning, masonry failures due to compression load and in plane shear failure mechanisms close to the openings; Typical actions/Interventions: General masonry confinement systems/ masonry elements encircling / flat arch and lintel strengthening. • Churches Description: Masonry structures with different types of plan (commonly: Latin cross, Latin cross plus naves, Latin cross plus aps, Latin cross plus additional corner, Latin cross plus chapels, Basilicas). Typical failure mechanism: Overturning of the facades or part of them (e.g Gable overturning), in plane shear failure, masonry failures due to compression load; Typical actions/Interventions: wall roofing and steel tie between the stone masonry layers in order to avoid overturning failures, flat arch lintel strengthening and strengthening of the opening areas/ masonry rehabilitation and strengthening system (e.g. inserting transversal units in the wall thickness aimed at connecting the three masonry leaves). • Heritage Houses (wood and masonry structure) Description: Light and resilient structures with a good response to seismic actions and a high level of tensile and compression strength. Typical failure mechanism: Connection failures / slenderness of the pillars. Typical actions/Interventions: improvement of connections with steel tie connectors and bar-shaped anchor plate / insertion of composite material bands (e.g. glass fibre) aimed at confining the pillars and increasing resistance to bending. • Heritage Houses (masonry structure) Description: Masonry structures with two outer stone wall layers and a mortar inner core. The stones usually are of small/medium size with very thin joints and poor mechanical properties. The stone pattern is random and often has vertical and not staggered joints favouring masonry cracks; moreover, the inner core material properties are often of a very poor quality thus increasing the vulnerability to horizontal actions. Transversal elements of connecting stones between the wall are not present. Orthogonal walls are often not linked to each other. Typical failure mechanism: Connection failures / Overturning Typical actions/Interventions: improvement of wall connections with steel tie connectors and bar-shaped anchor plates / improving connections between orthogonal wall by inserting steel ties in order to avoid overturning of the facades. • XX Century Public Buildings The concrete structures generally have local issues of concrete cover spalling and deterioration of reinforcing bars; generally cracks may be encountered due to plane shear failure mechanism and concrete failure due to compression load. These issues are due to a poor quality of the conglomerate to the reinforcing bars that are often not screwed down /in. 76 Final Report In order to reduce the described vulnerabilities it is possible to intervene locally restoring the concrete cover, applying anticorrosive treatments to the reinforcing bars. Particular attention should be paid to the condition of beam-pillar connection nodes, which have a major role in these kind of structures in order to absorb horizontal actions; where deemed unsuitable to fulfil that role, action is required in order to increase the strengthening inserting anchor plates or bands of composite materials in glass or carbon fibre. 4.1.4 Collection of typical intervention details The paragraph contains a collection of typical details to address the different structural damages observed for the 16 priority structures. The typical details include and refer partially to the various alternatives previously described (Chapter 3) using traditional and modern techniques and technologies adapted to the local construction techniques and materials. Thanks to the assessment carried out by architectural typologies, findings of activities 3.1 can be extended to all the structure characterised by the same typology and construction features as previously classified. International principles on cultural heritage conservation are used as a constant reference for the identification of risk reduction measures. 77 TYPICAL INTERVENTIONS A1 FOUNDATION INTERVENTIONS (REINFORCED CONCRETE RING BEAMS, AND CONCRETE AND STEEL MICROPILES) A1 FOUNDATION INTERVENTIONS (REINFORCED CONCRETE RING BEAMS, AND CONCRETE AND STEEL MICROPILES) Description: The work includes creation of reinforced concrete ring beams in order to obtain an enlargement at foundation level and its related footprint, aiming at a better distribution of tensions by decreasing their average stress. The ring beams run along the existing foundation, connected to each other with reinforced concrete beams, which have the function to redistribute vertical loads on the masonry. Under unstable soils conditions, steel micropiles can be used if necessary to avoid significant foundation failures. In the realization of concrete transversal elements, it is recommended to realise each transversal concrete element by spacing the subsequent one of at least 8 m from the previous one. Materials: concrete, steel bars, steel profiles for micropiles, drill rig machine. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drillings with drill rig machine, realization of works in reinforced concrete. $1.000/ml Skills: ordinary labourer, worker with drill rig machine handling training. NEW FOUNDATIONS WITH REINFORCED CONCRETE RING BEAMS AND CONCRETE PILES REINFORCED WITH STEEL ELEMENTS steel pile/100cm Ø200 reinforced with a steel tube 30 stone layers filling material between the two stone leaves 100 ring beam made of concrete, 40x60cm, reinforced with 2+2Ø16 rebars and steel stirrups Ø8/20cm 200 transversal ring beam made of concrete, 30x30cm, reinforced with 2+2Ø16 rebars and steel stirrups Ø8/20cm 100 steel pile/100cm Ø200 reinforced with a steel tube 30 40 40 filling material between the two stone leaves stone layers transversal ring beam made of ring beam made of concrete, concrete, 30x30cm, reinforced 40x60cm, reinforced with with 2+2Ø16 rebars and steel 2+2Ø16 rebars and steel stirrups stirrups Ø8/20cm Ø8/20cm 40 40 30 60 60 steel pile/100cm Ø200 steel pile/100cm Ø200 reinforced with a steel reinforced with a steel tube tube TYPICAL INTERVENTIONS A2 FOUNDATION INTERVENTIONS (UNDERPINNING) A2 FOUNDATION INTERVENTIONS (UNDERPINNING) Description: The work includes creation of underpinning in order to obtain an enlargement at foundation level and its related footprint, aiming at a better distribution of tensions by decreasing their average stress. The new foundation is made of the same stone used for the cladding; the enlargement size depends on the loads bearing on the masonry, but in general it should not be less than 1/3 (per side) of the original foundation. In the realization of the sub-foundation it is recommended to implement no more than one meter at a time by spacing the subsequent intervention of at least 8 m from the previous one. Materials: stone blocks, mortar. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: masonry demolition. $500/m3 Skills: ordinary labourer. DETAIL OF THE UNDERPINNING OF FOUNDATIONS filling material between the two stone leaves stone layers underpinning of foundations underpinning of foundations made of stones to enlarge made of stones to enlarge the existing foundation the existing foundation B1 TYPICAL INTERVENTIONS CRACKS INJECTION B1 CRACK INJECTIONS Description: The work includes the repair of the crack with hydrated lime mortar in order to restore the masonry continuity. Materials: hydrated lime mortar, crack injection kit. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: fluid mixture injection. $15/ml Skills: ordinary labourer. CRACK INJECTION existing stone multi-leaves masonry constituted of two stone layers with filling material between them crack iniejcted with hydrated lime mortar C1 TYPICAL INTERVENTIONS CRACKS STAPLING C1 CRACKS STAPLING Description: The work includes the repair of the crack with fiber-reinforced lime mortar in order to restore the masonry continuity and the insertion of "U" shaped steel rods in order to stop the progression of the crack. Materials: Stainless steel bars, epoxy resin, bars grouting kit, drilling tips. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: masonry perforations. $50/ml Skills: ordinary labourer. INJECTION AND STAPLING OF CRACK Ø6 steel inox bars existing stone multi-leaves masonry constituted of two stone layers with filling material between them crack iniejcted with fiber-reinforced lime mortar Ø6 steel inox bars existing stone multi-leaves masonry constituted of two stone layers with filling material between them Ø6 steel inox bars positioned after the injection of the crack with fiber-reinforced lime mortar TYPICAL INTERVENTIONS D1 REINFORCED PERFORATIONS ON MASONRY (STEEL BARS) D1 REINFORCED PERFORATIONS ON MASONRY (STEEL BARS) Description: The work includes insertion ofsteel bars in the wall thickness in order to effectively connect the three wall leaves composing the masonry; in this way the masonry behaves as single unit. The stone blocks, also, are individually connected to the core in order to avoid detachments due to compressive loads. The stone blocks are connected to the masonry through steel bolts and nuts. Materials: stainless steel bars, epoxy resin, bars grouting kit, drilling tips for holes deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill. $80/m 2 Skill: ordinary labourer. DISPOSITION OF STEEL BARS DETAIL OF THE POSITIONING OF STEEL BARS 200 existing stone multi-leaves masonry constituted of two stone layers with filling material between them M14 steel bars (imax =100cm) in Ø16 perforation with epoxy resin injections (in this 200 case it is necessary to perforate the stone, so there is no nut) M14 steel bars (imax =100cm) in Ø16 M14 steel bars (i max=100cm) in Ø16 perforation with perforation with epoxy resin injections epoxy resin (on this side there is the joint between injections (in this stones, so there is a nut) case there is the joint between stones, so there is a nut) existing stone multi-leaves masonry stone layers filling material between the two stone leaves M14 steel bars (imax =100cm) in Ø16 perforation with epoxy resin injections (on the M14 steel bars (i max=100cm) in Ø16 side with the joint perforation with epoxy resin injections between stones, we (on this side it is necessary to perforate have a nut; on the side the stone, so there is no nut) where it is necessary to perforate the stone, there is no nut) TYPICAL INTERVENTIONS D2 REINFORCED PERFORATIONS ON MASONRY (GFRP BARS) D2 REINFORCED PERFORATIONS ON MASONRY (GFRP BARS) Description: The work includes insertion of GFRP (glass fiber reinforced polymer) bars in the wall thickness in order to effectively connect the three wall leaves composing the masonry; in this way the masonry behaves as single unit. The resin is used to transfer the loads between rods and stone blocks, creating individual connections and avoiding detachments due to compressive loads. Materials: GFRP bars, epoxy resin, bars grouting kit. Availability: materials have to be imported, but are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill. $100/m 2 Skill: ordinary labourer. DISPOSITION OF GFRP BARS DETAIL OF THE POSITIONING OF GFRP BARS 200 existing stone multi-leaves masonry constituted of two stone layers with filling material between them Ø16 GFRP bars (imax=100cm) in Ø18 perforation 200 with epoxy resin injections Ø16 GFRP bars (imax=100cm) in Ø18 perforation with epoxy resin injections existing stone multi-leaves masonry Ø16 GFRP bars (i max=50cm) in Ø18 stone layers perforation with epoxy resin injections filling material between the two stone leaves Ø16 GFRP bars (i max =100cm) in Ø18 perforation with epoxy resin injections Ø16 GFRP bars (i max =100cm) in Ø18 perforation with epoxy resin injections TYPICAL INTERVENTIONS E1 REINFORCED PERFORATIONS ON MASONRY IN PROXIMITY OF OPENINGS (STEEL BARS) E1 REINFORCED PERFORATIONS ON MASONRY IN PROXIMITY OF OPENINGS (STEEL BARS) Description: The work includes insertion of steel bars in the stone blocks around the opening, connecting the blocks to the core in order to avoid detachments due to horizontal actions. The number of required bars is higher in this area than the rest of the masonry. The stone blocks are connected to the masonry through steel bolts and nuts. Materials: steel bars, steel bolts and nuts, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill. $800/each Skills: ordinary labourer. INCREASING OF STEEL BARS IN PROXIMITY OF DETAIL OF THE POSITIONING OF STEEL BARS OPENINGS M14 steel bars in Ø16 perforation with epoxy resin injections (on this side there is the joint between stones, so there is a nut) M14 steel bars in Ø16 perforation with epoxy resin injections (on this side it is necessary to perforate the stone, so there is no nut) DISPOSITION OF STEEL BARS 200 existing stone multi-leaves existing stone multi-leaves masonry constituted of two masonry stone layers with filling stone layers material between them M14 steel bars (i max =50cm) in filling material between the Ø16 perforation with epoxy two stone leaves resin injections (in this case it 200 is necessary to perforate the M14 steel bars (i max =50cm) stone, so there is no nut) in Ø16 perforation with epoxy resin injections (on the M14 steel bars (i max =50cm) in side with the joint between Ø16 perforation with epoxy stones, we have a nut; on the resin injections (in this case side where it is necessary to there is the joint between perforate the stone, there is stones, so there is a nut) no nut TYPICAL INTERVENTIONS E2 REINFORCED PERFORATIONS ON MASONRY IN PROXIMITY OF OPENINGS (GFRP BARS) E2 REINFORCED PERFORATIONS ON MASONRY IN PROXIMITY OF OPENINGS (GFRP BARS) Description: The work includes insertion of GFRP bars in the stone blocks around the opening, connecting the blocks to the core in order to avoid detachments due to horizontal actions. The number of required bars is higher in this area than the rest of the masonry. The stone blocks are connected to the masonry through steel bolts and nuts. Materials: GFRP bars, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill. $1.000/each Skills: ordinary labourer. INCREASING OF GFRP BARS IN PROXIMITY OF DETAIL OF THE POSITIONING OF GFRP BARS OPENINGS Ø16 GFRP bars (i max =50cm) in Ø18 perforation with epoxy resin injections DISPOSITION OF GFRP BARS 200 existing stone multi-leaves existing stone multi-leaves masonry constituted of two masonry stone layers with filling stone layers material between them Ø16 GFRP bars (i max =50cm) filling material between the in Ø18 perforation with epoxy two stone leaves resin injections 200 Ø16 GFRP bars (i max =50cm) in Ø18 perforation with epoxy resin injections Ø16 GFRP bars (i max =50cm) in Ø18 perforation with epoxy Ø16 GFRP bars (i max =50cm) resin injections in Ø18 perforation with epoxy resin injections TYPICAL INTERVENTIONS F1 CONNECTIONS OF WALL CORNERS WITH BARS DISPOSED IN A QUINCUNX PATTERN (STEEL BARS) F1 CONNECTION OF WALL CORNERS WITH BARS IN A QUINCUNX PATTERN (STEEL BARS) Description: The work includes insertion of 14mm diameter steel bars on cornerstones in towers and bell towers, structural typologies in which the edges are the zones most stressed by compression due to horizontal actions; stones not connected to the masonry tend to be dislocated due to instability. Materials: steel bars, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill. $80/ml Skills: ordinary labourer. STEEL BARS DISPOSED IN A QUINCUNX PATTERN DETAIL OF THE DISPOSITION OF STEEL BARS IN CORRESPONDENCE TO THE EDGES: PLAN AND SECTION M14 steel bars in Ø16 perforation with epoxy resin injections for the connections of edges with bars disposed in a quincunx pattern existing stone multi-leaves masonry M14 steel bars in Ø16 perforation with epoxy resin injections M14 steel bars in Ø16 perforation with epoxy resin injections for the connections of edges with bars disposed in a quincunx pattern existing stone multi-leaves masonry M14 steel bars in Ø16 perforation with epoxy resin injections for the connections of edges with bars disposed in a quincunx pattern TYPICAL INTERVENTIONS F2 CONNECTIONS OF WALL CORNERS WITH BARS DISPOSED IN A QUINCUNX PATTERN (GFRP BARS) F2 CONNECTION OF WALL CORNERS WITH BARS IN A QUINCUNX PATTERN (GFRP BARS) Description: The work includes insertion of GFRP bars on cornerstones in towers and bell towers, structural typologies in which the edges are the zones most stressed by compression due to horizontal actions; stones not connected to the masonry tend to be dislocated due to instability. Materials: GFRP bars, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill. $100/ml Skills: ordinary labourer. GFRP BARS DISPOSED IN A QUINCUNX PATTERN DETAIL OF THE DISPOSITION OF GFRP BARS IN CORRESPONDENCE TO THE EDGES: PLAN AND SECTION Ø16 GFRP bars, L=100cm in Ø18 perforation with epoxy resin injections for the connections of edges with bars disposed in a quincunx pattern every three rows of stones existing stone multi-leaves masonry Ø16 GFRP bars in Ø18 perforation with epoxy resin injections Ø16 GFRP bars, L=100cm in Ø18 perforation with epoxy resin injections for the connections of edges with bars disposed in a quincunx pattern existing stone multi-leaves masonry Ø16 GFRP bars, L=100cm in Ø18 perforation with epoxy resin injections for the connections of edges with bars disposed in a quincunx pattern TYPICAL INTERVENTIONS G1 CONNECTIONS IN THE WALL THICKNESS IN CORRESPONDENCE TO OPENINGS (STEEL BARS) G1 CONNECTIONS IN THE WALL THICKNESS IN CORRESPONDENCE OF OPENINGS (STEEL BARS) Description: The work includes insertion of 14mm diameter steel bars on stone blocks around the openings in towers and bell towers, structural typologies in which horizontal actions such as earthquake can cause concentrations of stresses with consequent dislocation of stones not connected to the masonry. Materials: steel bars, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Estimated unit cost: Compatibility: materials are fully compatible with existing masonry. $400/each Tasks: perforations with drill. Skills: ordinary labourer. STEEL BARS IN THE THICKNESS OF THE WALLS M14 steel bars, L=100cm (i max=50cm) in Ø16 IN PROXIMITY OF OPENINGS: PLAN perforation with epoxy resin injections in the thickness of the wall in correspondance to openings DISPOSITION OF STEEL BARS 200 existing stone multi-leaves masonry constituted of two stone layers with filling material between them M14 steel bars, L=100cm (imax =50cm) in Ø16 perforation with epoxy resin injections 200 M14 steel bars, L=100cm (imax =50cm) in Ø16 perforation with epoxy resin injections TYPICAL INTERVENTIONS G2 CONNECTIONS IN THE WALL THICKNESS IN CORRESPONDENCE TO OPENINGS (GFRP BARS) G2 CONNECTIONS IN THE WALL THICKNESS IN PROXIMITY OF OPENINGS (GFRP BARS) Descriptions: The work includes insertion of GFRP bars on stone blocks around the openings in towers and bell towers, structural typologies in which horizontal actions such as earthquake can cause concentrations of stresses with consequent dislocation of stones not connected to the masonry. Materials: GFRP bars, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Estimated unit cost: Compatibility: materials are fully compatible with existing masonry. $500/each Tasks: perforations with drill. Skills: ordinary labourer. GFRP BARS IN THE THICKNESS OF THE WALLS Ø16 GFRP bars, L=100cm (i max =50cm) in Ø18 IN PROXIMITY OF OPENINGS: PLAN perforation with epoxy resin injections DISPOSITION OF GFRP BARS 200 existing stone multi-leaves masonry constituted of two stone layers with filling material between them Ø16 GFRP bars, L=100cm (imax =50cm) in Ø18 perforation with epoxy resin injections 200 Ø16 GFRP bars, L=100cm (imax =50cm) in Ø18 perforation with epoxy resin injections Ø16 GFRP bars (i max =50cm) in Ø18 perforation with epoxy resin injections TYPICAL INTERVENTIONS H1 STEEL STRAND TIE-RODS BETWEEN THE WALLS OF THE NAVE H1 STEEL-STRANDS TIE-RODS BETWEEN THE WALLS OF THE NAVE Description: The work includes insertion of tie rods between the walls of the nave with the aim of preventing the relative distancing between parallel walls; in case of spans higher than 10m, 13mm diameter high resistance steel strands are advisable, in order to minimize rods weight and therefore the initial tie rod pull to be operated to obtain an acceptable bending. In addition, to split the tie rod span, a hanging system connected to the roof truss is proposed. The total weight of the tie rod is therefore reduced compared to a traditional steel tie rod. The connection to the masonry is made with steel bar-shaped anchor plates of appropriate size. Material: steel strands, lime mortar, steel bar-shaped anchor plates, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drilling with drill at height, implementation of the chain at height, need scaffolding. $8/kg Skills: labourer with training for working at a height. STEEL STRAND TIE-RODS WITH HANGING-UP SYSTEMS AND BAR-SHAPED ANCHOR PLATE bar-shaped existing stone anchor plate multi-leaves masonry Ø20 steel tie Ø13 steel bar-shaped anchor plate strand tie 10 with a Ø13 steel strand tie anchored to the plate with a Ø20 steel tie along the segment inside 70 0 9 the masonry in Ø24 perforation with epoxy resin injections 3 10 hanging-up system for the steel strand tie existing stone multi-leaves masonry stone layers bar-shaped anchor plate filling material between the two Ø20 steel tie stone leaves Ø20 steel tie in Ø24 Ø13 steel perforation with strand tie epoxy resin injections hanging-up system for the steel strand tie Ø13 steel strand tie connected with the Ø20 steel tie Ø20 steel tie in Ø24 perforation with epoxy resin injections TYPICAL INTERVENTIONS I1 TIE-RODS IN CORRESPONDENCE OF ARCHES I1 TIE-RODS IN CORRESPONDENCE OF ARCHES Description: The works include insertion of rods in the arches, with the purpose of preventing the relative distancing between piers and eliminate the load due to the constructive structure of the arch. Material: steel rods, lime mortar, steel bar-shaped anchor plates, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drilling with drill at height, implementation of the chain at height, need scaffolding. $1.500/each Skills: labourer with training for working at a height. CRACKS IN THE ARCHES OF PORTICO AND FOLLOWING POSITIONING OF TIE-RODS BEFORE THE INTERVENTION dislocation of the ashlars of the arch existing stone masonry arch crack crack existing stone masonry AFTER THE INTERVENTION repositioning of the ashlars of the arch existing stone masonry arch existing stone bar-shaped masonry Ø20 steel tie anchor plate Ø20 steel tie in Ø24 Ø20 steel tie in perforation with lime mortar Ø24 perforation injections: 45° connection with mortar with the steel bar, L=150cm injections BAR-SHAPED ANCHOR PLATE existing stone multi-leaves masonry stone layer filling material bar-shaped anchor plate with Ø20 Ø24 steel tie in Ø30 steel tie in Ø24 10 perforation with lime perforation with mortar injections lime mortar 70 0 injections 9 bar-shaped anchor plate 10 existing stone 3 multi-leaves masonry TYPICAL INTERVENTIONS I2 REINFORCED STAPLING IN CORRESPONDENCE OF ARCHES I2 REINFORCED STAPLING IN CORRESPONDENCE OF ARCHES Description: The works include insertion of steel bars in the arch, with the purpose of preventing the dislocation of the ashlars and of improving the connection between the arch and the masonry. Material: steel rods, lime mortar, bars grouting kit, drilling tips for perforations. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drilling with drill at height, implementation of the chain at height, need scaffolding. $2.000/each Skills: labourer with training for working at a height. CRACKS IN THE ARCHES OF PORTICO AND FOLLOWING POSITIONING OF BARS BEFORE THE INTERVENTION dislocation of the ashlars of the arch existing stone masonry arch crack crack existing stone masonry AFTER THE INTERVENTION L L repositioning of the ashlars of the arch existing stone masonry arch M12 steel bars positioned existing stone in alternated ashlars masonry L bar = 2*ashlar and injection with lime mortar TYPICAL INTERVENTIONS I3 STEEL PLATE AND STEEL BARS IN CORRESPONDENCE OF ARCHES I3 STEEL PLATE AND STEEL BARS IN CORRESPONDENCE OF ARCHES Description: The works include insertion of a calendered steel plate connected to the arch with steel bars, with the purpose of improving the resistance of the arch itself. Material: steel plate, steel rods, lime mortar, bars grouting kit, drilling tips for perforations. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drilling with drill at height, implementation of the chain at height, need scaffolding. $2.500/each Skills: labourer with training for working at a height. CRACKS IN THE ARCHES OF PORTICO AND FOLLOWING POSITIONING OF STEEL PLATES AND BARS BEFORE THE INTERVENTION dislocation of the ashlars of the arch existing stone masonry arch crack crack existing stone masonry AFTER THE INTERVENTION L 2/3 repositioning of the L ashlars of the arch existing stone calendered steel plate masonry arch 200x10mm and lime mortar between stones and steel plate existing stone M12 steel bars positioned in masonry alternated ashlars L bar = 2/3 ashlar and injection with lime mortar TYPICAL INTERVENTIONS I4 GFRP STIRPS AND ARAMID BARS IN CORRESPONDENCE OF ARCHES I4 GFRP STRIPS AND ARAMID BARS IN CORRESPONDENCE OF ARCHES Description: The works include insertion of a GFRP strip connected to the arch with aramid bars, with the purpose of improving the resistance of the arch itself. Material: GFRP strip, aramid bars, epoxy resin, bars grouting kit, drilling tips for perforations. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drilling with drill at height, implementation of the chain at height, need scaffolding. $2.500/each Skills: labourer with training for working at a height. CRACKS IN THE ARCHES OF PORTICO AND FOLLOWING POSITIONING OF GFRP STRIP AND ARAMID BARS BEFORE THE INTERVENTION dislocation of the ashlars of the arch existing stone masonry arch crack crack existing stone masonry AFTER THE INTERVENTION repositioning of the ashlars of the arch existing stone GFRP strip L=20cm and masonry arch epoxy resin between stones and strip existing stone M6 adamid bars positioned in masonry alternated ashlars L bar = 2/3 ashlar and injection with epoxy resin J1 TYPICAL INTERVENTIONS INTERVENTIONS ON TRANSEPT'S WALL (TIE-RODS IN THE WALL THICKNESS) J1 INTERVENTION ON TRANSEPT'S WALLS (INSERTION OF RODS IN THE WALL THICKNESS) Description: The works include insertion of rods within the wall in order to hinder the overturning mechanism and the bulging of transept's wall façade. The 20mm diameter steel rods are connected to the masonry with bar-shaped anchor plates. Material: steel rods, lime mortar, bar-shaped anchor plates, drilling tips for perforations deeper than 10m. Availability: materials are easily obtainable; drilling tips have to be imported. Compatibility: materials are fully compatible with existing masonry. Tasks: drilling with drill at height, implementation of the chain at height, need scaffolding. Skills: labourer with training for working at a height. Estimated unit cost: $8/kg EXTERNAL BAR-SHAPED ANCHOR PLATE OVER THE MASONRY existing stone multi-leaves masonry existing stone multi-leaves stone layer masonry filling material bar-shaped 10 anchor plate with M20 steel M20 steel tie in tie in Ø22 Ø22 perforation perforation with 70 0 with epoxy resin 9 epoxy resin injections injections bar-shaped 10 3 anchor plate INTERNAL ANCHOR PLATE UNDER THE PLASTER existing stone multi-leaves masonry stone layer existing stone filling material multi-leaves masonry M20 steel tie in Ø22 perforation with epoxy resin anchor plate injections under the plaster anchor plate with M20 steel under the plaster tie in Ø22 with M20 steel perforation with tie in Ø22 epoxy resin perforation with injections epoxy resin injections plaster TYPICAL INTERVENTIONS J2 INTERVENTIONS ON TRANSEPT'S WALLS (GFRP STRIPS WRAPPING) J2 INTERVENTION ON TRANSEPT'S WALLS (GFRP WRAPPING) Description: The works include insertion of GFRP strips at the interface between core and stone, in order to hinder the overturning mechanism and the bulging of transept's wall façades. Strips are inserted by removing a stone row, positioning the strips and finally placing the stone row in its original position. The strips are 20cm wide and are impregnated with epoxy resin. Materials: 20cm wide GFRP strips, epoxy resin, GFRP bars. Availability: materials have to be imported, but easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: drilling with drill at height, implementation of the strip at height, need scaffolding. Skills: labourer with training for working at a height. Estimated unit cost: $100/ml POSITIONING OF THE GFRP STRIPS WRAPPING removal of a row of stones, positioning of GFRP strip, L=20cm, repositioning of the stone, anchoring with Ø16 GFRP bar in Ø18 perforation with epoxy resin injections Ø16 GFRP bar existing stone multi-leaves masonry constituted of two stone layers with filling material between them removal of a row of stones, positioning of GFRP strip, L=20cm, repositioning of the stone, anchoring with Ø16 GFRP bar in Ø18 perforation with epoxy resin injections Ø16 GFRP bar Ø16 GFRP bar in Ø18 perforation removal of a row of stones, with epoxy resin injections positioning of GFRP strip, L=20cm, repositioning of the stone, anchoring with Ø16 GFRP bar in Ø18 perforation with epoxy resin injections existing stone multi-leaves masonry constituted of two stone layers with filling material between them removal of a row of stones, positioning of GFRP strip, L=20cm, repositioning of the stone, anchoring with Ø16 GFRP bar in Ø18 perforation with epoxy resin injections GFRP strip, L=20cm K1 TYPICAL INTERVENTIONS INTERVENTIONS ON EXISTING BUTTRESSES (RODS IN THE MASONRY THICKNESS) K1 INTERVENTION ON EXISTING BUTTRESSES (RODS IN THE MASONRY THICKNESS) Description: The works include insertion of rods within the buttresses in order to connect the stone leaf to the inner core, thus avoiding the stone blocks to be dislocated due to compression. The 20mm diameter steel rods are connected to the masonry with bar-shaped anchor plates. Material: steel rods, lime mortar, bar-shaped anchor plates, drilling tips for perforations deeper than 5m. Availability: materials are easily obtainable; drilling tips have to be imported. Estimated unit cost: Compatibility: materials are fully compatible with existing masonry. $8/kg Tasks: drilling with drill at height, implementation of the rods at height, need scaffolding. Skills: labourer with training for working at a height. EXTERNAL BAR-SHAPED ANCHOR PLATE OVER THE MASONRY POSITION OF TIE-RODS existing stone multi-leaves masonry bar-shaped anchor plate 10 with M20 steel tie in Ø22 perforation with epoxy resin injections 70 0 9 10 3 INTERNAL ANCHOR PLATE UNDER THE PLASTER existing stone multi-leaves masonry anchor plate under the plaster with M20 steel tie in Ø22 perforation with epoxy resin injections existing stone multi-leaves masonry stone layer filling material M20 steel tie in Ø22 perforation with epoxy resin M20 steel tie in Ø22 injections perforation with epoxy resin injections anchor plate under bar-shaped anchor the plaster with M20 plate steel tie in Ø22 perforation with filling material epoxy resin stone layer injections existing stone plaster multi-leaves masonry TYPICAL INTERVENTIONS K2 INTERVENTIONS ON EXISTING BUTTRESSES (GFRP WRAPPING) K2 INTERVENTION ON EXISTING BUTTRESSES (GFRP WRAPPING) Description: The works include insertion in existing buttresses of GFRP strips at the interface between core and stone, in order to hold the masonry and avoid the stone blocks to be dislocated due to compression. Strips are inserted by removing a stone row, positioning the strips and finally placing the stone row in its original position. The strips are 20cm wide and are impregnated with epoxy resin. Materials: 20cm wide GFRP strips, epoxy resin, GFRP bars. Availability: materials have to be imported, but easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drilling with drill at height, implementation of the strip at height, need scaffolding. $100/ml Skills: labourer with training for working at a height. WRAPPING WITH GFRP STRIPS removal of a row of stones, positioning of GFRP strip, L=20cm, repositioning of the stone, anchoring with Ø16 GFRP bar in Ø18 perforation with epoxy resin injections Ø16 GFRP bar existing stone multi-leaves masonry constituted of two stone layers with filling material between them removal of a row of stones, positioning of GFRP strip, L=20cm, repositioning of the stone, anchoring with Ø16 GFRP bar in Ø18 perforation with epoxy resin injections Ø16 GFRP bar POSITION OF GFRP STRIPS removal of a row of stones, positioning of GFRP strip, L=20cm, repositioning of the stone, anchoring with Ø16 GFRP bar in Ø18 perforation with epoxy resin injections existing stone multi-leaves masonry constituted of two stone layers with filling material between them removal of a row of stones, positioning of GFRP strip, L=20cm, repositioning of the stone, anchoring with Ø16 GFRP bar in Ø18 perforation with epoxy resin injections L1 TYPICAL INTERVENTIONS INTERVENTIONS ON TOWERS AND BELL TOWERS (TIE-RODS IN WALL THICKNESS) L1 INTERVENTION ON TOWERS AND BELL TOWERS (TIE RODS IN THE WALL THICKNESS) Description: The works include insertion of 20mm diameter steel rods in the thickness of the wall parallel to the masonry, in structural typologies such as towers and bell towers, with the purpose to encircle the building's volume and to obtain a confinement effect and thus improving the compression behaviour. This will hinder the transverse deformation due to the Poisson effect. Materials: steel rods, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill. $120/ml Skills: ordinary labourer. BAR-SHAPED ANCHOR PLATE OVER THE MASONRY existing stone multi-leaves masonry bar-shaped anchor plate 10 with M20 steel tie in M20 steel tie in Ø22 Ø22 perforation with perforation with epoxy resin injections epoxy resin injections 70 0 9 bar-shaped anchor plate 10 3 filling material stone layer existing stone multi-leaves masonry INTERVENTION ON TOWERS AND BELL TOWERS M20 steel tie in Ø22 perforation with epoxy resin injections with bar-shaped anchor plate L2 TYPICAL INTERVENTIONS INTERVENTIONS ON TOWERS AND BELL TOWERS (GFRP WRAPPING) L2 INTERVENTION ON TOWERS AND BELL TOWERS (GFRP WRAPPING) Description: The works include insertion of GFRP strips and 16mm diameter GFRP bars, in structural typologies such as towers and bell towers, with the purpose to encircle the building's volume and to obtain a confinement effect, this improving the compression behaviour. This will hinder the transverse deformation due to the Poisson effect. Materials: GFRP strips, GFRP bars, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill. $100/ml Skills: ordinary labourer. BAR-SHAPED ANCHOR PLATE OVER THE MASONRY removal of a row of stones, positioning of GFRP strip, L=20cm, repositioning of the stone, anchoring with Ø16 GFRP bar in Ø18 perforation with epoxy resin injections Ø16 GFRP bar existing stone multi-leaves masonry constituted of two stone layers with filling material between them removal of a row of stones, positioning of GFRP strip, L=20cm, repositioning of the stone, anchoring with Ø16 GFRP bar in Ø18 perforation with epoxy resin injections Ø16 GFRP bar INTERVENTION ON TOWERS AND BELFRIES GFRP strip, L=20cm and Ø16 GFRP bar in Ø18 perforation with epoxy resin injections TYPICAL INTERVENTIONS M1 STRENGTHENING OF STONE OR WOOD LINTELS AND CURVED LINTELS (STEEL PLATES) M1 STRENGTHENING OF STONE OR WOOD LINTELS AND CURVED LINTELS (STEEL PLATES) Description: The works include insertions of steel plates to the lintels or flat arches intrados, in order to improve the bending behaviour. Materials: steel plates, steel bolt and nuts, epoxy resin, bars grouting kit. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill. $150/each Skills: ordinary labourer. STEEL PLATES IN CORRESPONDENCE TO STONE STEEL PLATES IN CORRESPONDENCE TO WOOD LINTELS LINTELS steel plates 60x6mm fixed with Ø12 steel bars, L=15cm in Ø12 steel bars, L=15cm in Ø14 Ø14 perforation with epoxy perforation with epoxy resin resin injections injections steel plates 60x6mm STEEL PLATE STEEL PLATE late de red p calen m 0x6m m te 6 6 m el pla 0x ste e6 lat e lp ste TYPICAL INTERVENTIONS M2 REINFORCEMENT OF STONE OR WOOD LINTELS AND CURVED LINTELS (GFRP STRIPS) M2 STRENGTHENING OF STONE OR WOOD LINTELS AND CURVED LINTELS (GFRP STRIPS) Description: The works include insertions of GFRP strips to the lintels or flat arches intrados, in order to improve the bending behaviour. Materials: GFRP strips, GFRP bars, epoxy resin, bars grouting kit. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: perforations with drill. Estimated unit cost: $200/each Skills: ordinary labourer. GFRP STRIPS IN CORRESPONDENCE TO STONE GFRP STRIPS IN CORRESPONDENCE TO WOOD LINTELS LINTELS GFRP strips, W=20cm with lime mortar layer and GFRP bars (400+100)x10x7, GFRP strips, W=20cm with positioned under the existing beams and lime mortar layer and GFRP inside the masonry for about 15cm bars (400+100)x10x7 (removing the stone layer) removal of the stone layer after the positioning of scaffoldings removal of the stone layer after the positioning of scaffoldings GFRP STRIP GFRP STRIP 0cm 0cm =2 2 s ,W , W= s tri p trips RP R Ps GF GF TYPICAL INTERVENTIONS N1 REINFORCE OF VERTICAL WOODEN STRUCTURES (GFRP STRIPS) N1 REINFORCE OF VERTICAL WOODEN STRUCTURES (GFRP STRIPS) Description: The works include insertions of GFRP strips on the surface of wooden pillars, with the purpose of improving the pillar's bending behaviour and encircling the volume of the structure to obtain a confinement effect, thus improving the compression behaviour. This will hinder the transverse deformation due to the Poisson effect and improves the compression behaviour of the column, increasing its stability. Materials: GRFP strips, epoxy resin. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: placing of GFRP strips. $220/ml Skills: labourer trained to use GFRP strips. GFRP STRIPS IN CORRESPONDENCE TO WOOD VERTICAL STRUCTURES horizontal GFRP strips, W=20cm, positioned vertically every 100cm vertical GFRP strips, W=20cm horizontal GFRP strips, W=20cm, positioned horizontal GFRP strips, vertically every 100cm W=20cm, positioned vertically every 100cm vertical GFRP strips, W=20cm horizontal GFRP strips, W=20cm, positioned vertically every 100cm TYPICAL INTERVENTIONS O1 INTERVENTION ON WOOD ELEMENTS (REINFORCEMENT OF ELEMENTS) O1 INTERVENTION ON WOOD ELEMENTS (REINFORCEMENT OF ELEMENTS) Description: The works include insertion of steel plates connected to the wood elements with the aim to increase the resistence of the wood element itself in relation to vertical loads and horizontal loads such as earthquake and wind. Materials: steel screws, steel plates. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations on wooden elements. $8/kg Skills: labourer with training for working at a height. EXAMPLES OF WOOD ELEMENTS TO BE REINFORCED EXAMPLES OF REINFORCEMENT OF WOOD ELEMENTS TYPICAL INTERVENTIONS O2 INTERVENTION ON WOOD ELEMENTS (IMPROVEMENT OF CONNECTIONS AMONG WOOD ELEMENTS) O2 INTERVENTION ON WOOD ELEMENTS (IMPROVEMENT OF CONNECTIONS AMONG WOODEN ELEMENTS) Description: The works include insertion of new connections with steel plates and screws in wooden nodes where the connections are absent or insufficient or damaged by rust, with the aim to increase the resistence of the wood nodes in relation to vertical loads and horizontal loads such as earthquake and wind. Materials: steel screws, steel plates. Availability: materials are easily obtainable. Estimated unit cost: Compatibility: materials are fully compatible with existing masonry. $30/each Tasks: perforations on wooden elements. Skills: labourer with training for working at a height. EXAMPLES OF WOOD NODES WITH CONNECTIONS TO BE IMPROVED IMPROVEMENT OF CONNECTIONS AMONG WOOD IMPROVEMENT OF CONNECTIONS AMONG WOOD ELEMENTS WITH SCREWS ELEMENTS WITH STEEL PLATES AND SCREWS existing wood existing wood elements elements new connections among new connections among wood elements wood wood with screws elements with screws elements with steel plates and screws existing wood existing wood elements elements new connections among new connections among wood elements wood wood with screws elements with screws elements with steel plates and screws TYPICAL INTERVENTIONS P1 REPLACEMENT OR INTEGRATION OF DAMAGED WOODEN ELEMENTS P1 REPLACEMENT OR INTEGRATION OF DAMAGED WOODEN ELEMENTS Description: The works include replacing damaged wooden elements, which can no longer work properly. Materials: new wooden elements. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations on wooden elements. $30/m 2 Skills: labourer with training for working at a height. EXAMPLES OF DAMAGED WOOD ELEMENTS OR CONNECTIONS TO BE IMPROVED Q1 TYPICAL INTERVENTIONS RING BEAM (WOOD) Q1 RING BEAM (WOOD) Description: The work includes insertion of wooden ring beam, 40x20mm, along the perimeter of the top of the building, with the purpose of connecting the walls to ensure a box-like behaviour when the structure is subjected to horizontal forces. The ring beam, also, is also efficient in countering the façade overturning mechanism. The beam will be connected to the core with bars inserted in perforations injected with epoxy resin, in order to ensure the transfer of stress. Materials: wooden beams, steel bars, bolts and nuts, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill. $80/ml Skills: ordinary labourer. WOOD RING BEAM: PLAN AND SECTION 75 75 75 75 8 40 8 wood ring beam 40x20cm, positioned M14 steel bars L=115+20cm, positioned in the middle of the masonry every 75cm in a quincuncial pattern M10 steel bars L=27cm, for the connection between the wood trusses steel plate 700x100x6mm for the connection between the 10 wood trusses 70 70 steel plate 700x100x6mm M10 steel bars L=27cm, for the connection between the wood trusses 40 20 M14 steel bars L=115+20cm, positioned every 75cm wood ring beam 40x20cm, in a quincuncial pattern positioned in the middle of the masonry stone layers existing stone multi-leaves masonry Q2 TYPICAL INTERVENTIONS RING BEAM (TRUSS STEEL PLATES) Q2 RING BEAM (TRUSS STEEL PLATES) Description: The work includes insertion of steel plates, 15mm thick, along the perimeter of the top of the building, with the purpose of connecting the walls to ensure a box-like behaviour, when the structure is subjected to horizontal forces. The ring beam, also, is also efficient in countering the façade overturning mechanism. The plates will be connected to the core and to the external stone leaf with bars inserted in perforations injected with epoxy resin, in order to ensure the transfer of stress. Materials: steel plates, steel bars, bolts and nuts, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill, steel welding. $110/ml Skills: ordinary labourer. TRUSS STEEL RING BEAM: PLAN AND SECTION 150 15 15 15 15 15 15 15 15 15 steel plates L=150mm, s=15mm that M14 steel bars L=150cm welding compose a truss ring beam over the M14 steel bars L=25cm masonry corrugated sheet dismantling (and following metal reassembling) of the first part of the roof to build the ring beam steel plates L=150mm, s=15mm that compose a truss ring beam over the masonry 15 40 10 25 25 100 M14 steel bars L=150cm M14 steel bars L=25cm existing stone multi-leaves masonry stone layers Q3 TYPICAL INTERVENTIONS RING BEAM (GFRP MESH AND GFRP STRIPS) Q3 RING BEAM (GFRP STRIPS AND GFRP MESH) Description: The work includes insertion of GFRP mesh along the perimeter of the top of the building, with the purpose of connecting the walls to ensure a box-like behaviour, when the structure is subjected to horizontal forces. The ring beam, also, is also efficient in countering the façade overturning mechanism. The mesh will be connected to the core and to the external wall face with GFRP bars inserted in perforations injected with epoxy resin, in order to ensure the transfer of efforts. Materials: GFRP mesh, GFRP strips, GFRP bars, epoxy resin, bars grouting kit, drilling tips for perforations deeper than 1 m. Availability: materials have to be imported, but easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: perforations with drill. $150/ml Skills: ordinary labourer. GFRP RING BEAM: PLAN AND SECTION 150 20 20 GFRP strips, L=20cm GFRP mesh, 33x33mm GFRP "L" connections covering of GFRP (1000+100)x10x7mm with lime mortar corrugated sheet metal dismantling (and following reassembling) of the first part of the roof to build the ring beam covering of GFRP with lime mortar GFRP mesh, 33x33mm GFRP strips, L=20cm 10 10 10 10 10 40 57 57 100 GFRP "L" connections (1000+100)x10x7mm existing stone multi-leaves masonry stone layers TYPICAL INTERVENTIONS R1 INTERVENTION ON CONCRETE ELEMENTS (DAMAGED REBARS REPAIR) R1 INTERVENTION ON CONCRETE ELEMENTS (DAMAGED REBAR REPAIR) Description: The work includes repairing of damaged concrete elements by replacing of reinforcing bars damaged by rust, protection of bars next to the damaged ones and reconstruction of concrete cover. The original strength of the structural element is therefore restored. Materials: steel rebars, epoxy resin, bars grouting kit, rust protection products. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drilling on concrete elements, anti-corrosion treatment on steel bars, new concrete cover. $200/m 2 Skills: labourer with training for working at a height. INTERVENTION ON DAMAGED CONCRETE COVER AND BARS Step 0 Step 1 Step 2 Step 3 Existing reinforced Removal of the damaged treatment of the rebars Following realization of concrete pillar concrete cover with corrosion inhibitor reinforced render with and restoration of the electrowelded mesh concrete cover with Ø8/10x10cm thixotropy shrinkage compensating concrete fiber-reinforced mortar TYPICAL INTERVENTIONS R2 INTERVENTION ON CONCRETE ELEMENTS (STRENGTHENING WITH STEEL PLATES) R2 INTERVENTION ON CONCRETE ELEMENTS (STRENGTHENING WITH STEEL PLATES) Description: The work includes repairing of damaged concrete elements by using steel plates connected to the concrete element, with steel bars inserted in perforations injected with epoxy resin. The steel plates provide additional strength in the case of a load increase. Materials: steel bars, resin, steel plates, bars grouting kit Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drilling on concrete elements. $120/m 2 Skills: labourer with training for working at a height. INTERVENTION OF CONCRETE PILLARS equal leg angles steel profile 80x80x8mm steel profile 80 80x8mm/300mm plaster existing concrete pillar 80 new finishing plaser M12/60cm bars, L=20cm in Ø14/60cm perforations, 80 L=15cm injected with epoxy resin 80 80 80 equal leg angles steel profile 80x80x8mm 80 steel profile 80x8mm/300mm 300 existing concrete pillar 600 80 300 M12/60cm bars, L=20cm in Ø14/60cm perforations, L=15cm injected with 80 epoxy resin 300 600 80 300 80 TYPICAL INTERVENTIONS R3 INTERVENTION ON CONCRETE ELEMENTS (STRENGTHENING WITH GFRP STRIPS) R3 INTERVENTION ON CONCRETE ELEMENTS (STRENGTHENING WITH GFRP STRIPS) Description: The work includes repairing of damaged concrete elements by using GFRP strips connected to the concrete element with GFRP bars inserted in perforations injected with epoxy resin. The strips provide additional strength in the case of a load increase. Materials: GFRP strips, GFRP bars, epoxy resin. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drilling on concrete elements, anti-corrosion treatment on steel bars, new concrete cover. $150/m 2 Skills: labourer with training for working at a height. INTERVENTION OF CONCRETE PILLARS vertical GFRP strips, W=20cm plaster existing concrete pillar new finishing plaser horizontal GFRP strips, W=10cm, positioned vertically every 30cm 100 100 vertical GFRP strips, 100 W=20cm 300 existing concrete pillar 100 horizontal GFRP strips, 300 W=10cm, positioned vertically every 30cm 100 300 100 300 100 TYPICAL INTERVENTIONS R4 INTERVENTION ON CONCRETE ELEMENTS (SHEARWALLS STRENGTHENING) R4 INTERVENTION ON CONCRETE ELEMENTS (SHEARWALLS STRENGTHENING) Description: The work includes repairing of damaged concrete elements by using steel plates connected to the concrete element, with steel bars inserted in perforations injected with epoxy resin. The steel plates provide additional strength in the case of a load increase. Materials: steel bars, steel plates, epoxy resin, bars grouting kit Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drilling on concrete elements. $150/ml Skills: labourer with training for working at a height. CONSOLIDATION ON CONCRETE SHEARWALLS connection of the steel profile to the masonry with Ø14/50cm, Lmin=15cm perforations reinforced with Ø12/50 Lmin=15cm bars, injected with epoxy resin existing concrete masonry existing masonry existing concrete masonry equal leg angles steel profile 90x90x8mm connection of the steel profile to the equal leg angles steel masonry with Ø14/50cm, Lmin=15cm profile 90x90x8mm perforations reinforced with Ø12/50 Lmin=15cm bars, injected with epoxy resin TYPICAL INTERVENTIONS R5 INTERVENTION ON CONCRETE NODES (STRENGTHENING WITH STEEL PLATES) R5 INTERVENTION ON CONCRETE NODES (STRENGTHENING WITH STEEL PLATES) Description: The work includes repairing of damaged concrete nodes by using steel plates connected to the concrete element, with steel bars inserted in perforations injected with epoxy resin. The steel plates provide additional strength and additional stiffness in the case of a load increase. Materials: steel bars, steel plates, epoxy resin, bars grouting kit Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: drilling on concrete elements. $500/each Skills: labourer with training for working at a height. CONSOLIDATION ON CONCRETE NODES existing reinforced existing reinforced concrete structure concrete structure steel plates h=400mm, t=10mm, M14 steel bars in Ø16 perforation withe epoxy resin steel plates w=100mm, t=10mm existing reinforced concrete structure existing reinforced steel plates h=400mm, concrete structure t=10mm, M14 steel bars in Ø16 perforation withe epoxy resin S1 TYPICAL INTERVENTIONS INTERVENTIONS ON NON-STRUCTURAL ELEMENTS S1 INTERVENTION ON NON-STRUCTURAL ELEMENTS Description: The work includes securing non-structural elements which are at risk of failure when subjected to horizontal forces. It also includes the realization of new connections, in order to make the element integral to the structure and designed to withstand the forces they are subjected to. Materials: steel bars, resin, steel plates, bars grouting kit Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Tasks: drilling on concrete elements, anti-corrosion treatment on steel bars, new concrete cover. Skills: labourer with training for working at a height. EXAMPLES OF NON-STRUCTURAL ELEMENTS THAT NEED TO BE CONNECTED TYPICAL INTERVENTIONS T1 WALLS RECONSTRUCTION T1 WALLS RECONSTRUCTION Description: The work is proposed in case the construction of a new wall is required; employing the traditional construction technique of the Philippine walls, the insertion of transverse stones for the entire thickness of the wall is suggested, with the purpose of connecting the two external leaves with the inner core, improving the out of plane behaviour of the masonry. At least 1 cross element is required per square meter. Materials: cladding stones, filling, cross stones. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: building new masonry. $400/m3 Skills: commong labourer, labourer with training for working at a height. CONSTRUCTION OF NEW WALLS CONSTRUCTION OF NEW WALLS: EDGES stone elements that compose the edge and that are alternated in each row of stones stone elements that cross the thickness of the wall that are alternated in each row of stones stone elements that cross the thickness of the wall that are alternated in each row of stones stone elements that cross the thickness of the wall that are alternated in each row of stones stone elements that cross the thickness of the wall that are alternated in each row of stones TYPICAL INTERVENTIONS U1 FLOORING STRUCTURES RECONSTRUCTION (SINGLE WOOD PLANK) U1 FLOORING STRUCTURES RECONSTRUCTION (SINGLE WOOD PLANK) Description: The work is proposed in case the construction of a new wooden floor is required; employing the traditional construction technique of the Philippine intermediate flooring, the aim is to improve the quality of the support for the wooden beam on the wall. It is suggested to create a due support with new stones, allowing a better distribution of compressive loads on the masonry and using connectors to ensure the transfer of horizontal forces to the walls. Materials: new wooden elements, nails, stone blocks. Availability: materials are easily obtainable. Compatibility: materials are fully compatible with existing masonry. Estimated unit cost: Tasks: building new wooden slabs. $150/m 2 Skills: ordinary labourer, labourer with training for working at a height. CONSTRUCTION OF NEW FLOORS ON EXISTING MASONRY filling material between stone layers new wood planking the two stone leaves new wood beam new wood planking new wood beam the wood beam must be placed inside the masonry for minumum 50cm and must lie above two stones CONSTRUCTION OF NEW FLOORS ON NEW MASONRY: SECTION AND PLAN new wood planking new wood beam during the construction of the wall, the wood beam must be placed above the masonry for 2/3 of the thickness of the wall and a stone that crosses the masonry must be placed under the beam steel shaped plate for the new wood connection of the wood beam beam to the masonry, in particular to the stone that crosses the wall during the construction of the wall, the wood beam must be placed above the masonry for 2/3 of the thickness of the wall and a stone that crosses the masonry must be placed under the beam new wood beam steel shaped plate for the connection of the wood beam to the masonry, in particular to the stone that crosses the wall TYPICAL INTERVENTIONS U2 FLOORING STRUCTURES RECONSTRUCTION (DOUBLE WOOD PLANKS) U2 FLOORING STRUCTURES RECONSTRUCTION (DOUBLE WOOD PLANKS) Description: The work is proposed in case the construction of a new wooden floor is required; employing the traditional construction technique of the Philippine intermediate flooring, the aim is to improve the quality of the support for the wooden beam on the wall. It is suggested to create a due support with new stones, allowing a better distribution of compressive loads on the masonry and using connectors to ensure the transfer of horizontal forces to the walls. In case of spans higher than 4 meters, it is recommended to realize a double wood plank, with the aim to stiffen the floor and to allow a better distribution of horizontal forces to the walls. Materials: new wooden elements, nails, stone blocks. Availability: materials are easily obtainable. Estimated unit cost: Compatibility: materials are fully compatible with existing masonry. $170/m 2 Tasks: building new wooden slabs. Skills: ordinary labourer, labourer with training for working at a height. CONSTRUCTION OF NEW FLOORS ON EXISTING MASONRY filling material between stone layers new wood planking: the two stone leaves double layer new wood planking: new wood beam double layer new wood beam the wood beam must be placed inside the masonry for minumum 50cm and must lie above two stones CONSTRUCTION OF NEW FLOORS ON NEW MASONRY: SECTION AND PLAN new wood planking: double layer new wood beam during the construction of the wall, the wood beam must be placed above the masonry for 2/3 of the thickness of the wall and a stone that crosses the masonry must be placed under the beam steel shaped plate for the new wood connection of the wood beam beam to the masonry, in particular to the stone that crosses the wall during the construction of the wall, the wood beam must be placed above the masonry for 2/3 of the thickness of the wall and a stone that crosses the masonry must be placed under the beam new wood beam steel shaped plate for the connection of the wood beam to the masonry, in particular to the stone that crosses the wall Loboc - Tower Cortes - Tower Building Asset Loboc - Church Cortes - Church Panglao - Tower Dimiao - Church Cortes - Convent Panglao - Church Dimiao - Convent Alburquerque - Church Alburquerque - Convent Loboc - Mortuary Chapel Manila - St. Augustin - Tower Manila - Metropolitan Theatre Manila - St. Augustin - Church Manila - St. Augustin - Convent Maribojoc - Punta Cruz - Tower DATA TABLE LEGEND OF PRIORITY: - Low Low High High Medium Medium Medium Medium Medium Code of the Seismic Risk intervention Medium-Low Medium-Low Medium-High Medium-High Medium-High Medium-High Medium-High (FaMIVE Results) Foundation interventions (reinforced concrete ring beam, A and concrete and steel micropiles) [A1] or underpinning [A2]) B Crack injection [B1] C Crack stapling [C1] Reinforced perforations on D masonry IMMEDIATE-TERM INTERVENTION (steel bars [D1] or GFRP bars [D2]) Reinforced perforations on E masonry in proximity of openings (steel bars [E1] or GFRP bars [E2]) Connections of wall corners with F bars in a quincunx pattern (steel bars [F1] or GFRP bars [F2]) Connections in the wall thickness G in correspondence of openings (steel bars [G1] or GFRP bars [G2]) MEDIUM-TERM INTERVENTION Steel strand tie-rod between the H walls of the nave [H1] Tie-rod in correspondence of I arches [I1] Intervention on transept's walls J (tie-rod in wall thickness [J1] or GFRP wrapping [J2]) Intervention on existing buttresses K (rod in the masonry thickness [K1] or GFRP wrapping [K2]) Interventions on towers and bell L towers (ros in the wall thickness [L1] or GFRP wrapping [L2]) Strengthening of stone or wood M lintels and curved lintels (steel plates [M1] or GFRP strips [M2]) Reinforce of vertical wooden N structures (GFRP strips [N1]) Intervention on wood elements (reinforcement of elements [O1] or O improvement of connections among elements [O2]) Repalcement or integration of P damaged wood elements [P1] Ring beam (wood [Q1], truss steel Q plates [Q2], GFRP mesh and GFRP strips [Q3]) Interventions on concrete R elements [R1] [R2] [R3] [R4] [R5] Intervention on non-structural S elements [S1] T Wall reconstruction [T1] Flooring structures reconstruction U (single wood plank [U1] or double wood planks [U2]) RECOMENDATIONS FOR IMMEDIATE AND MEDIUM-TERM RISK REDUCTION MEASURES FOR PRIORITY STRUCTURES COMBINATION BETWEEN BUILDINGS AND INTERVENTIONS Final Report 4.2 Recommendations for the 16 priority structures This paragraph includes a collection of suggested immediate and medium-term risk reduction measures for the 16 selected priority structures. Measures proposed have been elaborated based on the visual surveys carried out and on the vulnerability assessment results obtained in the previous phases of the project. The level of reliability provided by the use of FaMIVE has also been considered, and results cross-checked and integrated with the on site investigation campaign results as well as with the visual inspection and structural suervey carried out on site. For each building, a brief architectural introduction is followed by the vulnerability assessment results; hence, a summary table of priority interventions is completed with a list of immediate and mediu-term risk reduction measures. Interventions are identified by codes, that make reference to paragraph 4.1, where typical intervention are described and illustrated. 4.2.1 Loboc Church The building was still in use as a church when the 2013 earthquake severely hit it; due to the serious damaged occurred, it is currently closed. The church follows a cruciform plan with one nave, a narthex and choir loft above it, and transept. The original Jesuits baroque-style façade, provided with two side turrets, was later on covered by a neoclassical portico-façade. Buttresses alongside elevations also constitute a later addition. Vertical structures are made of multi-leaves masonry; horizontal structures are made of timber framing for intermediate flooring and wood truss system for the roof, covered by galvanised iron sheets. Of great architectural, aesthetic and historic value, the church is a fine example of Spanish-era architecture that has evolved and expanded during time. The building was enriched by external stone carvings, five wooden retablos and an entire ceiling mural by Ray Francia, and Canuto and Ricardo Avila. The complex exhibits traditional building technology and indigenous materials. 119 Final Report Vulnerability assessment: FaMIVE results Summary of priority risk reduction measures identified 120 Final Report Immediate term risk reduction measures Ref. Intervention B1 Crack injections D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) H1 Steel-strands tie-rods between the walls of the nave I1 Tie-rods in correspondence of arches J1 Intervention on the transept’s walls (insertion of rods in the wall thickness) J2 Intervention on the transept’s walls (GFRP wrapping) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) P1 Replacement or integration of damaged wooden elements Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) S1 Intervention on non-structural elements T1 Walls reconstruction U1 Flooring structures reconstruction (single wood plank) U2 Flooring structures reconstruction (double wood planks) 4.2.2 Loboc Tower Due to the major collapses occurred due to the 2013 earthquake, the building is currently closed, although it might be in use as bell tower before the calamity. The tower was built as an addition to the church along the riverbanks, serving both as a bell tower and watchtower. The building follows an octagonal plan on four stories, two of which have totally collapsed. Vertical structures are made of multi-leaves masonry; elevations were decorated with pilasters, capitals, blind niches and volutes. The timber pitched roof covered with metal sheets has also completely collapsed. Of great architectural, aesthetic and historic value, the tower is an adjunct to the church. The complex is said to be the largest and oldest Jesuit infrastructure in Bohol. It underwent accretions throughout its development, and it exhibits traditional building technology and indigenous materials. 121 Final Report Vulnerability assessement: FaMIVE results Summary of priority risk reduction measures identified 122 Final Report Immediate term risk reduction measures Ref. Intervention B1 Crack injections D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) L1 Intervention on towers and bell towers (tie rods in the wall thickness) L2 Intervention on towers and bell towers (GFRP binding) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) P1 Replacement or integration of damaged wooden elements Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) S1 Intervention on non-structural elements T1 Walls reconstruction U1 Flooring structures reconstruction (single wood plank) U2 Flooring structures reconstruction (double wood planks) Medium-term risk reduction measures Ref. Intervention G1 Connections in the wall thickness in correspondence of openings (steel bars) G2 Connections in the wall thickness in correspondence of openings (GFRP bars) 4.2.3 Loboc Mortuary Chapel Former mortuary chapel, later on adoration chapel, currently the building hosts the parish administration offices, previously located into the convent collapsed in 2013. The Chapel, later addition to the religious complex, follows a hexagonal plan on a single storey built of a multi-leaves masonry. The timber pyramidal roof is covered by metal sheets. The exteriors are enriched with architectural motifs including pilasters, capitals, moulding, cornices and medals. In its interiors, the chapel still houses a baroque retablo similar to the side altars of the church. 123 Final Report Adjunct to the Loboc church, the chapel participate to the whole site historical, architectural and aesthetic values as a fine example of Spanish colonial architecture that has evolved and expanded during time. The complex exhibits traditional building technology and indigenous materials. Vulnerability assessment: FaMIVE results Summary of priority risk reduction measures identified 124 Final Report Immediate term risk reduction measures Ref. Intervention B1 Crack injections Medium-term risk reduction measures Ref. Intervention D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) 4.2.4 Albuquerque Church The building is in use as a church, not having suffered major damages during the 2013 earthquake. The church follows a cruciform plan, with three naves, narthex and choir loft above, and a transept. Rare Philippine hardwood timber posts, exceptional in height and girth, delimitate the three naves, and are believed to date back to a previous church. The belfry upon the masonry portico-façade, marked by giant concrete columns, constitutes later reinforced concrete additions. Vertical structures are made of multi-leaves masonry; pediments of the church facades are made of tabique, while a particular fitting of the stonework with diagonal cuts is visible on the back facade. The rafter-type roofing system is entirely made of timber. Of high historical and architectural significance, the church testifies to the evolution of the construction techniques from tabique to coral stone multi-leaves masonry up to the use of reinforced concrete, typical testimony of American-period insertions to Spanish-era churches. 125 Final Report Vulnerability assessment: FaMIVE results Summary of priority risk reduction measures identified 126 Final Report Immediate term risk reduction measures Ref. Intervention B1 Crack injections H1 Steel-strands tie-rods between the walls of the nave I1 Tie-rods in correspondence of arches J1 Intervention on the transept’s walls (insertion of rods in the wall thickness) J2 Intervention on the transept’s walls (GFRP wrapping) K1 Intervention on existing buttresses (rods in the masonry thickness) K1 Intervention on existing buttresses (GFRP wrapping) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) P1 Replacement or integration of damaged wooden elements Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) R1 Intervention on concrete elements (damaged rebars repair) R2 Intervention on concrete elements (strengthening with steel plates) R3 Intervention on concrete elements (strengthening with GRFP strips) R4 Intervention on concrete elements (shearwalls strengthening) R5 Intervention on concrete nodes (strengthening with steel plates) Medium-term risk reduction measures Ref. Intervention A1 Foundation interventions (reinforced concrete ring beams, and concrete and steel micropiles) A2 Foundation interventions (underpinning) D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) N1 Reinforce of vertical wooden structures (GFRP strips) 127 Final Report 4.2.5 Alburquerque Convent The building is in use as convent, not having suffered major damages during the 2013 earthquake. Built following a rectangular plan on two storeys, it is detached from the church but connected to it through a stone portico, unique case on the island. Twin stairway leads from the ground floor to the upper level, provided with an open-air terrace on the eastern wing of the convent. Of high architectural and historical significance, the convent testifies to the traditional typology recurrent for convents, heritage houses and schools, using indigenous materials and mixed construction techniques: multi-leaves masonry for the ground floor and wooden frames, boards and tabique walls at the upper level, characterised by interesting strip motifs for lighting and ventilation. Vulnerability assessment: FaMIVE results 128 Final Report Summary of priority risk reduction measures identified Immediate term risk reduction measures Ref. Intervention B1 Crack injections O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) P1 Replacement or integration of damaged wooden elements S1 Intervention on non-structural elements Medium-term risk reduction measures Ref. Intervention A1 Foundation interventions (reinforced concrete ring beams, and concrete and steel micropiles) A2 Foundation interventions (underpinning) D1 Reinforced Perforations on masonry (steel bars) D2 Reinforced Perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) I1 Tie-rods in correspondence of arches K1 Intervention on existing buttresses (rods in the masonry thickness) K2 Intervention on existing buttresses (GFRP wrapping) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) N1 Reinforce of vertical wooden structures (GFRP strips) Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) 129 Final Report 4.2.6 Cortes Church The building was still in use as a church when the 2013 earthquake severely hit it; due to the serious damaged occurred, it is currently closed. The church follows a cruciform plan, with one nave, narthex, choir loft and a transept. An octagonal baptistery is adjunct to the west side, and an octagonal drum supports a squat pyramid - dome above the crossing. The masonry portico-façade has completely collapsed, and also damaged are many coralstone bas-relief and carvings visible on the elevations. The building is characterised by a detached belfry, the upper portions of which are built of reinforced concrete. Vertical structures are made of multi-leaves masonry with some concrete additions (belfry, two concrete pillars support the timber choir loft), while facades pediments realized in timber. The rafter-type roofing system is made of timber. The church has high historical, architectural and aesthetic significance, displaying traditional construction materials and techniques typical of the Spanish era, as well as concrete addition typical of the American period. The retablo mayor was characterised by motifs typical of the late 18th century Philippine art, and some other decorative items (doorway carvings, bells) may confirm the tradition that these were handed down by the mother parish of Maribojoc, following a universal age-old practice. 130 Final Report Vulnerability assessment: FaMIVE results Summary of priority risk reduction measures identified 131 Final Report Immediate term risk reduction measures Ref. Intervention B1 Crack injections C1 Cracks stampling D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) H1 Steel-strands tie-rods between the walls of the nave M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) P1 Replacement or integration of damaged wooden elements Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) S1 Intervention on non-structural elements T1 Walls reconstruction U1 Flooring structures reconstruction (single wood plank) U2 Flooring structures reconstruction (double wood planks) Medium-term risk reduction measures Ref. Intervention A1 Foundation interventions (reinforced concrete ring beams, and concrete and steel micropiles) A2 Foundation interventions (underpinning) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) 132 Final Report Cortes Tower Vulnerability assessment: FaMIVE results Summary of priority risk reduction measures identified 133 Final Report Immediate term risk reduction measures Ref. Intervention B1 Crack injections C1 Cracks stampling D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) P1 Replacement or integration of damaged wooden elements Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) Medium-term risk reduction measures Ref. Intervention A1 Foundation interventions (reinforced concrete ring beams, and concrete and steel micropiles) A2 Foundation interventions (underpinning) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) G1 Connections in the wall thickness in correspondence of openings (steel bars) G2 Connections in the wall thickness in correspondence of openings (GFRP bars) L1 Intervention on towers and bell towers (tie rods in the wall thickness) L2 Intervention on towers and bell towers (GFRP binding) 4.2.7 Cortes Convent The convent was in use as school when the 2013 earthquake severely hit it; due to the serious damaged occurred, it is currently closed. The I-shaped two storeys building is attached to the church. Undated modifications and additions were made over time to the original structure. The principal stairway has a banister that carried Art Deco motifs similar to those in the tower of Anda (1950-1952). Of high architectural and historical significance, the convent testifies to the traditional typology recurrent for convents, heritage houses and schools, using indigenous materials and mixed construction techniques: multi-leaves masonry for the ground floor and wooden frames, boards, tabique and tabique pampango walls at the upper level, characterised by interesting strip motifs for lighting and ventilation. 134 Final Report Vulnerability assessment: FaMIVE results Summary of priority risk reduction measures identified 135 Final Report Immediate term risk reduction measures Ref. Intervention B1 Crack injections C1 Cracks stampling D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) P1 Replacement or integration of damaged wooden elements Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) S1 Intervention on non-structural elements T1 Walls reconstruction U1 Flooring structures reconstruction (single wood plank) U2 Flooring structures reconstruction (double wood planks) Medium-term risk reduction measures Ref. Intervention A1 Foundation interventions (reinforced concrete ring beams, and concrete and steel micropiles) A2 Foundation interventions (underpinning) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) 4.2.8 Dimiao Church The building was still in use as a church when the 2013 earthquake severely hit it; due to the damaged occurred, it is currently closed. Service rooms on the back of the buildings are being currently used as workplace for producing religious wooden furniture. The church follows a cruciform plan, with one nave, narthex, choir loft, and wide transept. The facade is completed by two octagonal side belfries. The building is supported by two only buttresses of noticeable dimensions. Vertical structures are made of multi-leaves masonry, while horizontal structures are made of timber framing for intermediate flooring and a wood truss system for the roof, covered by galvanised iron sheets. 136 Final Report The first religious settlement in Dimiao is believed to be to the north of the church, where the current Ermita ruins and a walled cemetery stand. The structure near the Ermita entrance has been interpreted as the original visita. The present Church was built between 1797 and 1815. All the interior furnishing (retablos, pulpit, pipe organ) dates back to the 19th century. The church, its adjacent Ermita ruins and its architectural elements underwent many accretions throughout their development. The church, of historical and architectural value, displays traditional construction materials and techniques typical of the Spanish era religious complexes. Unlike most of Bohol churches, the building does not have a portico-facade but two side turrets recalling the original layout of Loboc church. Vulnerability assessment: FaMIVE results 137 Final Report Summary of priority risk reduction measures identified Immediate term risk reduction measures Ref. Intervention B1 Crack injections D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) H1 Steel-strands tie-rods between the walls of the nave J1 Intervention on the transept’s walls (insertion of rods in the wall thickness) J2 Intervention on the transept’s walls (GFRP wrapping) K1 Intervention on existing buttresses (rods in the masonry thickness) K2 Intervention on existing buttresses (GFRP wrapping) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) P1 Replacement or integration of damaged wooden elements Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) Medium-term risk reduction measures Ref. Intervention A1 Foundation interventions (reinforced concrete ring beams, and concrete and steel micropiles) A2 Foundation interventions (underpinning) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) L1 Intervention on towers and bell towers (tie rods in the wall thickness) L2 Intervention on towers and bell towers (GFRP binding) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) 138 Final Report 4.2.9 Dimiao Convent The convent is currently in use, both as a convent and as school. The L-shaped two storeys building is attached to the church. Although several modifications occurred over time, much of the original structures and materials is still extant. Of high architectural and historical significance, the convent testifies to the traditional typology recurrent for convents, heritage houses and schools, using indigenous materials and mixed construction techniques: multi-leaves masonry for the ground floor and wooden frames, boards and tabique and tabique pampango walls at the upper level. The brick stove in the kitchen is one of the surviving examples of its kind. Vulnerability assessment: FaMIVE results 139 Final Report Summary of priority risk reduction measures identified Immediate term risk reduction measures Ref. Intervention B1 Crack injections D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) P1 Replacement or integration of damaged wooden elements U1 Flooring structures reconstruction (single wood plank) U2 Flooring structures reconstruction (double wood planks) Medium-term risk reduction measures Ref. Intervention A1 Foundation interventions (reinforced concrete ring beams, and concrete and steel micropiles) A2 Foundation interventions (underpinning) C1 Cracks stapling E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) N1 Reinforce of vertical wooden structures (GFRP strips) Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) 4.2.10 Panglao Church The building is in use as a church, not having suffered major damages during the 2013 earthquake. The church follows a cruciform plan, with one nave, a cantilevered choir loft above the main entrance, and transept. A neoclassical portico-façade and belltower attached to the buildings constitutes reinforced concrete later additions. Four buttresses per side support longitudinal walls. Vertical structures are built of 140 Final Report multi-leaves stone masonry; pediments upon the end wall of the transepts are of galvanized steel sheets, and so the drum upon the transept crossing. The rafter-type roofing system is made of steel profiles, covered with corrugated galvanized steel sheets. The church is of historical and architectural significance. The church testifies to the evolution of the construction techniques from coral stone multi-leaves masonry up to the use of reinforced concrete and steel trusses typical of subsequent construction periods upon Spanish-era churches. Interiors are enriched by carved wooden furnishing and ceiling paintings dating back to the 19th or early 20th century. Vulnerability assessment: FaMIVE results 141 Final Report Summary of priority risk reduction measures identified Immediate term risk reduction measures Ref. Intervention D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) H1 Steel-strands tie-rods between the walls of the nave I1 Tie-rods in correspondence of arches J1 Intervention on the transept’s walls (insertion of rods in the wall thickness) J2 Intervention on the transept’s walls (GFRP wrapping) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) 4.2.11 Panglao Watchtower The building is not in use, although it stands as a monument frequently visited by tourists. Built following a hexagonal plan on four stories made of multi-leaves stone masonry; walls are of noticeable depth (up to 3 meters), tapering from the bottom to the top. The original timber pitched roof, with ceramic tile, was lost already before 2013. The slanting vault upon the entrance stairway is built of timber, stone blocks, and mortar poured between them, while the ground floor is backfilled. Of high architectural and historical value, the watchtower exhibits the use of traditional building technology and indigenous materials, and testifies to historical developments in the Island. Built in 1851, it was aimed at the extirpation of pirate raids from the south which was aggressively pursued in the 19th century. It is the tallest tower in Bohol with views to Cebu, Negros, Siquijor and even Camiguin Island. 142 Final Report Vulnerability assessment: FaMIVE results Summary of priority risk reduction measures identified 143 Final Report Immediate term risk reduction measures Ref. Intervention B1 Crack injections C1 Cracks stampling D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) L1 Intervention on towers and bell towers (tie rods in the wall thickness) L2 Intervention on towers and bell towers (GFRP binding) P1 Replacement or integration of damaged wooden elements Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) T1 Walls reconstruction U1 Flooring structures reconstruction (single wood plank) U2 Flooring structures reconstruction (double wood planks) Medium-term risk reduction measures Ref. Intervention G1 Connections in the wall thickness in correspondence of openings (steel bars) G2 Connections in the wall thickness in correspondence of openings (GFRP bars) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) 4.2.12 Punta Cruz Watchtower The building is not in use, although it stands as a monument frequently visited by tourists. The watchtower follows a triangular plan, with a hexagonal belfry built on the upper level. The structures is made of coralstones multi-leaves masonry, and the intermediate flooring is constituted supported by a timber frame supporting layers of brick, sand, mortar. The stairway leading to the upper level is covered by a masonry vault, collapsed in 2013. Also collapsed the pitched roof constituted of a timber truss placed over a timber frame, covered by galvanized steel sheets. Also known as Castillo de San Vicente Ferrer, built in 1796 as part of the defense system in the Visayas against slave raiders and pirates from the south. Historically and strategically significant, the structure is planned along the lines of the isosceles triangle, unique case in the county, conferring also high architectural value. 144 Final Report Vulnerability assessment: FaMIVE results Summary of priority risk reduction measures identified 145 Final Report Immediate term risk reduction measures Ref. Intervention B1 Crack injections C1 Cracks stampling D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) L1 Intervention on towers and bell towers (tie rods in the wall thickness) L2 Intervention on towers and bell towers (GFRP binding) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) P1 Replacement or integration of damaged wooden elements Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) T1 Walls reconstruction U1 Flooring structures reconstruction (single wood plank) U2 Flooring structures reconstruction (double wood planks) Medium-term risk reduction measures Ref. Intervention G1 Connections in the wall thickness in correspondence of openings (steel bars) G2 Connections in the wall thickness in correspondence of openings (GFRP bars) 4.2.13 San Agustin Church The building is in use as a church. The basilica-type plan is supported by side chapels. Originally provided with two symmetrical side belfries, only one of them still standing: due to the 1880 earthquake, the tower over General Luna street had to be demolished; debris used to fill up the base of the mentioned tower. Vertical structures are built of regularly cut blocks of volcanic tuff with an interior fill of rubble and lime mortar. Side chapels are covered with groin vaults, while a barrel vault is upon the main nave. Roofing truss system is composed of steel profiles with timber slats. Seat of the Augustinian order, springboard for the evangelization of other Asia countries, the church has been assigned outstanding value for its style and design, deriving from the physical conditions in the 146 Final Report Philippines and with an important influence on later church architecture in the region. Specific attribute is found in its monumental and massive appearance, which illustrates a fortress/protective-like character in response to pirates, marauders and to the geologic conditions of a country that is prone to seismic activities. Made of volcanic tuff stone, the church is the only surviving example of stone vaulted structure in the Philippines. Vulnerability assessment: FaMIVE results 147 Final Report Summary of priority risk reduction measures identified Immediate term risk reduction measures Ref. Intervention I1 Tie-rods in correspondence of arches Medium-term risk reduction measures Ref. Intervention D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) H1 Steel-strands tie-rods between the walls of the nave M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) 148 Final Report San Agustin Tower Vulnerability assessment: FaMIVE results tower Summary of priority risk reduction measures identified . 149 Final Report Immediate term risk reduction measures Ref. Intervention D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) G1 Connections in the wall thickness in correspondence of openings (steel bars) G2 Connections in the wall thickness in correspondence of openings (GFRP bars) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) 4.2.14 San Agustin Convent The building is in use as repository for religious artifacts and for tourism purposes. Built following a quadrangular plan and attached to the church, it is characterised by the presence of a wide courtyard. The courtyard corridors are covered with stone vaults. Vertical structures are made of regularly cut blocks of volcanic tuff with an interior fill of rubble and lime mortar. Stone vaults for intermediate horizontal structure. The rafter-type roofing system is made of steel. Seat of the Augustinian order, springboard for the evangelization of other Asia countries, the complex has been assigned outstanding value for its style and design, deriving from the physical conditions in the Philippines and with an important influence on later church architecture in the region. Specific attribute is found in its monumental and massive appearance, which illustrates a fortress/protective-like character in response to pirates, marauders and to the geologic conditions of a country that is prone to seismic activities. Made of volcanic tuff stone, the complex is the only surviving example of stone vaulted structure in the Philippines. 150 Final Report Vulnerability assessment: FaMIVE results Summary of priority risk reduction measures identified 151 Final Report Immediate term risk reduction measures Ref. Intervention I1 Tie-rods in correspondence of arches Medium-term risk reduction measures Ref. Intervention D1 Reinforced perforations on masonry (steel bars) D2 Reinforced perforations on masonry (GFRP bars) E1 Reinforced Perforations on masonry in proximity of openings (steel bars) E2 Reinforced perforations on masonry in proximity of openings (GFRP bars) F1 Connection of wall corners with bars in a quincunx pattern (steel bars) F2 Connection of wall corners with bars in a quincunx pattern (GFRP bars) M1 Strengthening of wood or stone lintels and curved lintels (steel plates) M2 Strengthening of wood or stone lintels and curved lintels (GFRP strips) O1 Intervention on wood elements (reinforcement of elements) O2 Intervention on wood elements (improvement of connections among wooden elements) Q1 Ring beam (wood) Q2 Ring beam (truss steel plates) Q3 Ring beam (GFRP strips and GFRP mesh) 4.2.15 Manila Metropolitan Theatre The building is not in use and in state of abandon. Public building dating back to the early 20th century, the theatre is symmetrical plan with a central block (the theatre per se) with the lobby, seating area, stage, and backstage; two equal wings connected to the lobby curve towards identical rectangular blocks. Additions operated over time include a pair of walls to the sides of the theatre, encroaching into the pair of courtyards and eliminating the reflecting pools originally located in the courtyards. Structures are made of reinforced concrete frames (columns and beams) and reinforced masonry shear walls. The roof trusses over the seating and stage are made of steel and had recently been rehabilitated. The building has a very high architectural and aesthetic value, being the most impressive Art Deco structure of the Philippines, with rich ornamentation as the stylized reliefs. Cast concrete statues inside and outside the building realised by Francesco Ricardo Monti. Lobby murals painted by the first National Artist Fernando Amorsolo. Socially significant due to the performing, musical and literary arts that flourished during the era of the building which became the wellspring of many national artists’ achievements. 152 Final Report Summary of priority risk reduction measures identified Immediate term risk reduction measures Ref. Intervention A1 Foundation interventions (reinforced concrete ring beams, and concrete and steel micropiles) A1 Foundation interventions (underpinning) R1 Intervention on concrete elements (damaged rebars repair) R2 Intervention on concrete elements (strengthening with steel plates) R3 Intervention on concrete elements (strengthening with GRFP strips) R4 Intervention on concrete elements (shearwalls strengthening) R5 Intervention on concrete nodes (strengthening with steel plates) S1 Intervention on non-structural elements 153 Final Report ANNEXES Annex 1. Site Investigation Campaign A. Implementation procedures of site investigation campaign 1. Introduction 2. Reference framework 3. Actions undertaken to prevent negative impacts during the testing campaign B. Reports on implemented tests 4. Albuquerque Church 5. Cortes Church 6. Dimiao Church 7. Panglao Watchtower C. Test campaign attendance sheet Annex 2. Numerical Analysis of Retrofitting Options 1. Dimiao Church 2. Albuquerque Church 3. Panglao Watchtower Annex 3. Analyses Of Options For Reduction Of Multi-Hazard Risks In Bohol (Structural Survey - Damage Survey - Structural Interventions) 1. Dimiao Church 2. Albuquerque Church 3. Panglao Watchtower 154