Evaluation of the Inelastic Deformation Demands in Regular Steel Frames by Comparing the Results of the Pushover Method with the Nonlinear Time Histories Analysis Under the Near-Fault Pulse-type Earthquake

In this research, the capability of elastic load patterns, including suggested patterns in prevalent seismic codes, and modified elastic patterns such as the Method of Modal Combinations (MMC) and the Upper-Bound Analysis (UPBA) in estimating the nonlinear demands of steel moment frame are evaluated by pushover method. Afterward the results of pushover analysis compared with the results of Nonlinear Time History Analysis (NTHA) affected by near-fault pulse-type ground motion. This study, not only tried to investigate the ability of load patterns to be used in pushover methods but also obtained different inelastic demands such as absolute displacement story (RD), Inter-story Drift Ratio (IDR), global ductility (μg) and story ductility (μs). Eventually, the error values of each load pattern were reported. The most important innovation of this research is the analytical study of the ability of various patterns of pushover methods against the values derived from nonlinear time history analysis (affected by near-fault earthquakes) in computing the parameters of the general and interstory deformation (which has been less consideration in previous studies) by applying the effect of higher modes.