Research on earthquake action for seismic appraisal and retrofit of earthquake-damaged buildings

For the earthquake-damaged buildings, it is quite necessary to do research on adjustment of earthquake action in their seismic appraisal and retrofit. The earthquake generation model was established based on the Homogeneous Poisson Process, and the probability distribution of earthquake action was embodied by Extreme Value Type (II and III), then the conversion relation among seismic intensity, peak ground acceleration(PGA) and maximum horizontal earthquake influence coefficient were obtained, as well as their own seismic hazard curve formulas. Moreover, the basic principles of equal precautionary intensity, equal exceeding probability and equal return period were illustrated respectively, and several categories of earthquake-damaged buildings were listed with different classification principles. In the end, based on the continuous seismic service life of earthquake-damaged buildings, an available approach according to equal return period principle was proposed to modify the corresponding earthquake action, and the main steps were given here. Based on comparative research, it is concluded that the equal return period method is more reasonable than the equal precautionary intensity method and the equal exceeding probability method to reflect the risk of earthquake-damaged buildings reencountering similar precautionary earthquakes in their continuous seismic service life, and therefore it can be more appropriately used to modify the earthquake action for seismic appraisal and retrofit of earthquake-damaged buildings.