采用不同目标谱的RC框架结构一致地震倒塌风险评价

It is necessary to make shift from the current traditional paradigm of uniform hazard to the more rational paradigm of uniform risk for seismic fortification parameters determination and seismic design method of engineering structures. To achieve the goal of uniform risk prevention and control, it needs dual-control of both absolute and relative collapse risks of structures under earthquakes, and also needs to take target spectrum to select ground motion records to compute and check the two kinds of structural collapse risks. In this paper, the reinforced concrete (RC) frame structures are taken as case studies, and three target spectra, including code design spectrum, uniform hazard spectrum and uniform risk spectrum, are utilized to select the ground motion records. The incremental dynamic analysis (IDA) technique is used to derive the collapse fragility curves and functions. The analytical seismic hazard function using seismic fortification parameters and the probabilistic seismic hazard function based on seismic safety evaluation results of building site are respectively chosen to compute and verify the seismic collapse risks of the case-study structures. It is shown by the analysis results that, using code design spectrum to evaluate the seismic collapse risk of structures will get the conservative evaluation results, while using the site-specific spectra can more rationally realize the goal of uniform risk seismic design, since it can consider the variability in seismic hazards in different building sites due to different seismic tectonic environments.