Displacement-based Probabilistic Seismic Demand Analysis And Structural Seismic Design Research

Seismic evaluation of structural performance is one of the main research contents in performance-based seismic design theory. Probabilistic analysis of structural displacement responses for different seismic intensities is difficult but principal for performance evaluation. Displacement-based design is an important approach to realize the idea of performance-based design. However the current studies in this field are still at the stage of discussion about some concepts, and away from practical application and implementation into design codes. Focused on structural probabilistic seismic demand analysis and displacement-based seismic design, this dissertation involves the following work:1. Estimating the structural target displacement is essential for Pushover analysis method to be applied to the evaluation of structural seismic performance. The target displacement of a structure can be predicted by capacity spectrum method, where the demand curves are often constructed by elastic-plastic response spectra. The present research on elastic-plastic response spectrum is mostly on constant-ductility strength demand spectrum. After investigating the differences in conception and calculation between constant-strength ductility demand spectrum and constant-ductility strength demand spectrum, the former is proposed for the demand curves. Combined with the capacity curve from Pushover analysis, the target displacement and seismic performance of a structure can be estimated.2. The intensity and frequency content of an earthquake ground motion can be considered separately by introducing normalized yield strength coefficient and constructing constant-strength ductility demand spectrum, similar to the seismic factor and dynamic amplification factor curve in elastic response spectrum. According to the site types and characteristic periods, the collected records are classified. Under each set of records, nonlinear time history response analysis for plentiful bilinear single-degree-of-freedom systems (SDOF) is carried out. Based on these results, and conditional on given normalized yield strength coefficient and structural fundamental period, the probabilistic distribution type of ductility demands is checked by hypothesis test, also the mean and standard deviation of ductility demands are obtained by nonlinear multiple regression analysis. As a result, probabilistic ductility demand spectrum can be constructed. Utilizing probabilistic ductility demand spectrum and the characteristic of conditional probabilistic distribution, simplified...