Seismic screening and structural investigation of heritage buildings for adaptive reuse: a survey study at Iloilo City, Philippines

Building adaptive reuse has been a popular strategy for cultural heritage conservation of structures for it serves two basic objectives of preserving heritage structures and promoting cultural heritage and tourism. Adaptive reuse is the adaptation of an old structure to allow the introduction of a modern function into the old structure. Old buildings are not demolished but recycled into modern uses. This strategy, however, needs a careful and thorough assessment of these existing heritage buildings to assure their resilience and sustainability to future hazards. Heritage buildings for adaptive reuse due to age and structural deterioration are highly vulnerable to hazards like earthquakes. Moreover, these buildings when used for commercial purposes may be subjected to additional loads due to changes in function. Considering the age of the structure, conformity to new design codes, additional loads imposed by unit modification, and the new function brought about by adaptive reuse of these structures, there is a need to assess these buildings to assure their safety and continuous use. Promoting adaptive reuse of heritage buildings and tourism is most appropriate in heritage zones like Calle Real in Iloilo City, the site for the case study. This paper presents a rapid seismic screening of buildings to prioritize a population of heritage buildings in a heritage zone for further detailed inspection. A site survey of the buildings was conducted at the heritage zone of Calle Real, Iloilo City in terms of their current use, and current condition to determine potential structural, maintenance, and functional issues related to resilience and to recommend future improvements in the implementation of adaptive reuse of heritage structures in cities and towns to assure their sustainability

A multi-hazard risk prioritisation framework for cultural heritage assets

Multi-hazard risk assessment of building portfolios is of primary importance in natural-hazard-prone regions, particularly for the prioritisation of disaster risk reduction and resilience-enhancing strategies. In this context, cultural heritage assets require special consideration because of their high vulnerability to natural hazards – due to ageing and types of construction – and their strong links with communities from both an economic and a historical–sociocultural perspective. This paper introduces a multi-hazard risk prioritisation framework specifically developed for cultural heritage assets. The proposed framework relies on a multilevel rapid-visual-survey (RVS) form for the multi-hazard exposure data collection and risk prioritisation of case-study assets. Because of the multilevel architecture of the proposed RVS form, based on three levels of refinement and information, an increasing degree of accuracy can be achieved in the estimation of structural vulnerability and, ultimately, structural risk of the considered assets. At the lowest level of refinement, the collected data are used for the computation of seismic-risk and wind-risk prioritisation indices, specifically calibrated in this study for cultural heritage assets with various structural and non-structural features. The resulting indices are then combined into a unique multi-hazard risk prioritisation index in which the intangible value of cultural heritage assets is also considered. This is achieved by defining a score expressing the cultural significance of the asset. The analytic hierarchy process is extensively used throughout the study to reduce the subjectivity involved in the framework, thus obtaining a simplified yet robust approach which can be adapted to different building typologies. The proposed framework is applied to 25 heritage buildings in Iloilo City, Philippines, for which innovative, non-invasive techniques and tools for improved surveying have also been tested. Thermal and omnidirectional cameras have helped in the collection of structural data, together with drones for the inspection of roofs. Results of the study are presented and critically discussed, highlighting advantages and drawbacks of the use of new technologies in this field