Selection of earthquake ground motion accelerograms for structural design in Hong Kong

Abstract

Hong Kong is situated in an intraplate area of low to moderate seismicity, where recorded strong-motion accelerograms are scarce. As part of the seismic design process, dynamic time-history analysis is sometimes required for assessing the seismic performance of structures. Hence, earthquake accelerograms representative of various local design hazard levels are needed. This study aims to develop a methodology for building up a database of earthquake accelerograms for the Hong Kong region which can be used for the analysis and design of a variety of structural and geotechnical systems. An outline of the previous probabilistic seismic hazard analysis studies conducted for Hong Kong is first presented and several design earthquake scenarios are determined, which contribute most to the local seismic hazard given a specific return period. The median response spectra and conditional mean spectra of the selected earthquake scenarios for reference rock sites are then derived based on the component attenuation model. The conditional mean spectra are then used as the target spectra for the selection and scaling of recorded accelerograms sourced from the available global database. Finally, a suite of conditional mean spectra–compatible accelerograms for rock sites is presented, from which event-specific and site-specific accelerograms are generated through dynamic site response analysis.