Seismic fragility curves for tall wall concrete buildings in Malaysia under near-field earthquakes

Abstract

Tall buildings are widespread in Malaysia and the majority of them are designed to carry only gravity and wind loads. Seismic regulations are not taking into account for such buildings in both design stage and construction stage. This study addresses the seismic behaviour of tall buildings in Malaysia by developing fragility curves for two tall concrete walls. Both buildings are 80m height with two different configurations. The first building with five car park levels and the second one with three car park levels. The structural system of both buildings is moment resisting frame (MRF) at the parking levels and shear wall system at the residential levels. The reference structures were subjected to fifteen near field earthquake records. Fragility curves were obtained by relating the obtained seismic demands from nonlinear time history analysis to the peak ground acceleration using a reliable statistical model. It was found from fragility curves of building (A) the exterior frame is more vulnerable than interior frame for both damage states, while in building (B) the probabilities of both frames to have severe damage were close to each other, but for minor damage, fragility curves illustrate that the exterior frame was more fragile than interior frame. The developed fragility curves demonstrated that the seismic behaviours of both buildings were different under the same ground motion intensities. Results showed that building (A) with five car-park levels has better resistance to seismic load compare to building (B) with three car-park. It can be concluded that design concept of such buildings against wind and gravity is adequate in fulfilling the required performance if the design PGA is less than 0.2g.