Seismic Response and Analysis of an Instrumented Building in Jakarta Subjected to the January 14th, 2022 Banten Earthquake

On January 14th, 2022, a strong earthquake with a magnitude of M6.6 occurred in the south of Java Island, Indonesia, at a depth of 40 km. The earthquake was of an intensity up to MMI V (moderate shaking) in the area near the epicenter of the earthquake. The earthquake was also felt in Jakarta (MMI II), which is about 226 km away from the epicenter. A building in Jakarta was instrumented with accelerometers and recorded the floor vibration accelerations during the event. The record shows that the peak acceleration at the 12th floor was 3.614 times higher than the peak acceleration at the ground floor. The acceleration records were then analyzed to obtain the natural frequencies of the building, the displacement at the ground and 12th floors, and the vibration characteristics of the building due to the earthquake shaking. In order to study the performance of the building for future larger earthquake, a computer model of the building was also built. Comparison of the computer model of the building with the characteristics calculated using the recorded data was carried out for adjusting the behavior of the building. Parameters used for adjustment are building’s natural periods and damping ratios. After attempts to adjust those parameters, the model building is then used for calculating the threshold when the building enters inelastic phase and the percentage of inter-story drift. This can be used as a structural warning sign should larger earthquakes strike in the future.