Study Of The Synthetic Application On Pushover And Inelastic Demand Spectra Analysis

Performance-based seismic design (PBSD) has become more and more popular phrase for the next generation of seismic design. Determining the target displacement in-duced by strong ground motion is an important part of PBSD, which essentially verifies the allowable structural damage and service functional objectives that structures should maintain during the earthquake. The study of target displacement is crucial to realize the PBSD.Based on the current application and research of nonlinear static analysis,which called pushover analysis, and inelastic demand spectra (IRS), the combination of two methods is introduced to attempt to find a accurate, simple and convenient approach that determines the target displacement .Through that, PBSD will be applied to the practical structure design, and the true sense of the structural performance-based design will be re-alized.This paper utilizes MPA and IRS to propose a simple approach to obtain the mul-ti-degrees of freedom (MDOF) system's target displacement. The approach describes as follows: First, the capacity spectra curve of the elastic structure due to its first nth vi-bration mode can be exactly developed from pushover analysis of the structure subjected to the invariant lateral force distribution; Second, the target displacement of the respective modes can be determined with IRS; At last, the correspond MDOF system's target dis-placement is determined according to square root of sum of squares (SRSS) rules. The ap-proach developed in this paper not only considers the affection of the high modes, but also avoids the elastic response spectra of high damping and equivalent single degree of free-dom linear systems. According to the above, the 8-story reinforced concrete 2D-frame modeled in SAP2000 is used to evaluate the approach. Compared to the results from nonlinear history analysis of the same structure, the results from this method are matched relatively, and the errors are considerable, which show the method that incorporate MPA with IRS to obtain target displacement is a simple and effective method.