Seismic fragility curves for winddesigned-buildings in Hong Kong

Abstract

This chapter presents a simple analytical method to generate seismic fragility curves for low-rise to high-rise buildings in Hong Kong. The seismic vulnerability is assumed proportional to the sectional areas of the column and shear walls of the structure. Three wind-code-designed buildings are selected for the analysis, namely a 6-storey school building by the Architectural Services Department, and a 21- storey residential building at Mei Foo Sun Chuen, and a 40-storey residential building of the Hong Kong Housing Authority. Instead of using intensity, seismic hazard is prescribed in terms of peak ground acceleration. The adopted response spectra are site-dependent and depend on whether the design earthquakes are near field or far field. The seismic responses of buildings are analyzed using the equivalent static force approach for multi-degree-of-freedom-oscillators, expressed in terms of the fundamental site period and epicentral distances. The ductility distribution of buildings is then formulated as a lognormal distribution. Finally, the vulnerability of the structure is given as fragility curves. The results indicate that damage probability is highly sensitive to the number of storey or building height, structural scheming, and functional usage of the buildings and other parameters such as site condition and epicentral distance are equally crucial to the structural seismic vulnerability.