Seismic assessment of metallic neo-gothic church: deterioration and safety of early structural design

Abstract

The San Sebastian Basilica, located in Manila in Philippines, consists of a unique architectural monument in the area, representing the colonial neo-gothic style of the 19th century. The site where the church is constructed is characterized by high seismicity, and as an attempt to make it earthquake resistance, it was constructed by steel, after multiple collapses of previous versions of the church. The aim of this study is to assess the safety of the Basilica, by integrating an in-situ diagnostic campaign. More specifically, the investigation works performed in the last decade are enriched by experimental dynamic identification tests. After obtaining the dynamic properties of the church, a detailed numerical model is constructed and calibrated to match the experimental results. The final model is then employed and several non-linear static analyses are performed in order to assess the capacity of the church. A number of numerical and methodological issues are highlighted throughout the process, before concluding about the safety, the damage state and the main structural vulnerabilities of the Basilica.