Some Aspects of Earthquake Resistant Design in Canada and China

Abstract

This chapter considers recent improvements in the seismic design codes of Canada and the People's Republic of China by comparatively analyzing the earthquake provisions of the National Building Code of Canada (NBCC 1990) with those of the Aseismic Design Building Code of China (ADBCC 1989). The topics discussed include the probability of exceedance and return periods controlling earthquake zoning, and the selection of ground motion parameters in relation to earthquake magnitude and epicentral distance; the assignment of ground motion intensity levels associated with the minor, moderate, and major earthquakes contemplated in the design philosophy governing earthquake codes; the evaluation of earthquake loads including suggested methods of analysis and incorporating the influence of importance of structure, soil–structure interaction, vertical ground motion, and design spectrum; and the strength and service load requirements including control of drift. Canada and China use their own, but analogous, methods to assess seismic risk and develop seismic zoning maps. Characteristics of the ground motion spectrum at a given site depend on earthquake magnitude and epicentral distance, and the response of different structures varies in relation to the earthquake and structural characteristics. The Canadian Code uses both peak horizontal ground acceleration (PHA) and peak horizontal ground velocity (PHV) as zoning parameters for design. By using both parameters, National Building Code of Canada (NBCC) takes into account information on the frequency content of potential earthquakes. The main earthquake analysis approaches of both NBCC and ADBCC are based upon response spectrum theory. Various methods for evaluating seismic response of buildings are suggested in NBCC and ADBCC, which are also discussed in the chapter. Both NBCC and ADBCC prescribe special measures to ensure that structures designed for essential public services remain operative alter an earthquake. Both NBCC and ADBCC intend that all portions of a structure be designed to act as an integral unit in resisting earthquake action.