specialty journal of engineering and applied science
Nonlinear Dynamic Analysis Method for Irregular Steel Moment Frame in 15-Story Structures
Fatemeh Abdollahpur, Elham Moadab, Narqes Isazadeh
The use of nonlinear static methods in estimating the performance of structures during earthquakes has been highly concerned by engineers. To further improve the results of nonlinear static methods, it is useful to concern the effect of all highest modes on the structure response. In this study, the results of previous studies on nonlinear static methods and considering the effect of highest modes on the irregular structures behavior in height will be reviewed. To estimate the seismic requirements in irregular buildings at height, the average maximum relative floor displacement and floor shear were obtained by MPA method and compared with the results of nonlinear time history analysis method. The study aims to estimate the correlation between MPA results and nonlinear dynamic analysis according to comparison with the US FEMA regulations and to examine the similarities and differences between each of them. In this study, the conditional mean spectrum will be used to estimate seismic parameters. Response and design spectrum are the basis of all earthquake load modeling in earthquake engineering. The target spectrum is used is one of the most important topics in earthquake engineering. Research in recent years has shown that the conditional mean spectrum can be a more appropriate target spectrum for selecting earthquakes which get the mean response spectrum in all frequencies with the condition of specific spectral acceleration in the desired frequencies. The results of nonlinear static analysis indicate that the models for capacity curve the is slightly different, but regular structures show more capacity. The yield displacements of the structure are almost identical.