Research on Lateral Load Distribution for Asymmetric Frame Structures in Pushover Analysis

摘要

Nonlinear static procures(NSP)are widely used in performance based seismic design since it provides designers a relatively simple approach to estimate inelastic structural response measures. However, conventional lateral load patterns used in NSPs can not satisfy the practical engineering demand, such as the effect of higher modes and the particularity of irregular building. Considering the torsion effects caused by the earthquake, two methods calculated the lateral load distributions for asymmetric structures, which are called Method of Two-times Distribution and Method of Storied Distribution, are established. Through pushover analysis and time-history analysis of a R.C. plan asymmetric structure, the validity of the procedure is validated by comparing response quantities such as story displacement,inter-story drift ratio and distribution of hinges. It is shown that the distribution of hinges obtained from pushover analysis is accord with that of practical damage under earthquake;Story displacement and inter-story drift ratio are in accord with the result of time-history analysis;and precision of the two methods is better enough to evaluate the capacity of asymmetric structures in pushover analysis.