Influence of earthquake mechanisms to the seismic response of steel moment frames

Recent studies conducted on Steel Moment Frames (SMFs) highlight the importance of considering the effect of certain characteristics of earthquake ground motions (GMs) such as duration and spectral shape in their seismic response. Although their acceleration response spectra have mainly characterized ground motions in seismic standards, these studies indicate that the probability of collapse is sensitive to the GMs' duration. This represents a concern in areas with a different tectonic mechanism, such as South-America, and Pacific Northwest U.S., where subduction processes mainly generate GMs. It is well-known that the duration and spectral shape of subductions earthquakes are quite different from crustal earthquakes. Motivated by these issues, this research presents a parametric study to assess building height sensitivity to metrics such as inter-story drift ratios and floor accelerations, considering GMs records from subduction and crustal earthquakes carefully selected and scaled. The scientific basis of this research is a series of nonlinear dynamic analyses conducted on SMFs (varying in height) at different seismic hazard levels. Two hazard levels are considered in this study: a) Life safety and b) Collapse prevention. The paper intends to understand the sensitivity of engineering demand parameters (i.e., drifts and floor accelerations) of SMFs to different earthquake mechanisms (i.e., crustal earthquakes vs. subduction earthquakes). The GMs records of subduction earthquakes consist of a set of GMs representative of South America and Japan's seismicity. The GMs records set of crustal earthquakes collects large magnitude-long distance events representative of Southern California.