Investigation and Analyzing the Resistance of Non-Linear Structures Against Failure Under the Influence of Successive Seismic Loads

This article examines the resistance reduction factor of the system with one degree of freedom (SDOF) which is subjected to the ground motions of the sequence of main-earthquake type - aftershock. Both displacement ductility and cumulative damage are considered in the reduction factor. Recordings of main earthquakes and aftershocks have been collected and classified according to the characteristics of the place. The post-earthquake ground motions are successively scaled to five levels of relative intensity. Based on nonlinear time history analysis of SDOF systems, the effects of natural period, ductility coefficient, damage index and aftershock have been studied statistically. The results show that the post-earthquake ground motion has a significant effect on the resistance reduction factors and the damage-based resistance reduction factor is about ۰.۶-۰.۹ times the ductility-based resistance reduction factor. Finally, an empirical expression for the resistance reduction coefficient has been established by regression analysis.

کلیدواژه ها:

power reduction factor ، inelastic response spectrum ، ground motion damage index