SEISMIC FRAGILITY CURVES FOR WIND-DESIGNED-BUILDINGS IN HONG KONG

摘要

This paper presents a simple analytical method to generate seismic fragility curves for low-rise to high-rise buildings in Hong Kong. In particular, the seismic vulnerability is assumed proportional to the sectional areas of the column and shear walls of the structure. Three wind-code-designed buildings were selected as examples for the present analysis, namely a 6-story school building by the Architectural Services Department, and a 21-story residential building at Mei Foo Sun Chuen and a 40-story residential building of the Hong Kong Housing Authority (HKHA). Instead of using intensity, seismic hazard is prescribed in terms of peak ground acceleration (PGA) in the present study. 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 log-normal 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 story or building height, structural scheming, and functional usage of the buildings; other parameters such as site condition and epicentral distance are equally crucial to the structural seismic vulnerability. The conclusion should also be expected for other wind-designed buildings in Hong Kong and other parts of the world.