Seismic analysis of the San Sebastian Basilica (Philippines)

This paper presents the evaluation of the seismic performance of the San Sebastian Basilica, which included dynamic identification tests, preparation of numerical models and pushover analyses. The San Sebastian Basilica, located in Manila and inaugurated in 1891, consists of a fully prefabricated steel structure that has maintained its original design, interior finishes and materials. The dynamic identification tests were carried out using ambient vibration, which allowed to estimate six modes (2.53 Hz to 5.81 Hz). The FEM models employ an evolutionary process to assess the importance of the addition of various elements on the dynamic properties of the basilica. The seismic analysis allowed the conclusion that the transverse direction of the Basilica presents the lowest capacity, namely 2.5 g and 3.6 g for the uniform and first mode loading pattern, respectively. However, further works should be conducted to conclude on the safety of the basilica for seismic action.