Fragility and seismic risk of public building structures due to earthquake loads (Case study: Manahan Sports Building)

Abstract Earthquake disaster is a natural disaster with a small probability of occurrence but with a large risk of consequences. Indonesia is an earthquake-prone area which is flanked by 3 plates. which results in Indonesia becoming an earthquake-prone area. This paper analyzes the seismic performance and risk of public buildings of indoor sports buildings which has a inclined column with an elliptical cross-section in Manahan District, Surakarta city. From 1867-2022, there were 10 big earthquakes that occurred in several nearby cities in Surakarta. The seismic risk analysis was conducted by constructing a fragility function depicted in the form of a fragility curve. The analysis procedure starts with developing a 3D finite element model in the computer and applying pushover loads so that the structure achieves nonlinear behavior with material specifications and loading in accordance with the Indonesian National Standard 1726-2019 regulations and resulting in capacity curves, then converted into a capacity spectrum curve. Damage limits are set based on ATC-40 and HAZUS MH-MR 5 criteria. The fragility function is defined as the conditional probability of exceeding the damage limits set for various earthquake intensities. From this study, the probability of building damage based on ground acceleration in Surakarta (Sa=0,36g) with ATC-40 criteria is obtained on the X axis with Immediate Occupancy damage of 13.29% and Life safety of 3.21%, on the Y axis the Immediate Occupancy limit is 55.51% and Life safety is 13.89%. For HAZUS MH-MR 5 guidelines on the X-axis the probability for slight damage is 60.29%, moderate 30.97%, extensive 3.21% and complete 0.42%, and for the Y-axis slight is 93.76%, moderate 73.06%, extensive 12.24% and complete 9.47%.