Seismic Response of Moment‐Resisting Steel and Composite Multi‐Story Buildings

Abstract

The seismic design of multi‐story steel buildings requires balancing structural efficiency, drift control, and material economy. This study presents a parametric comparison of moment‐resisting steel and steel‐concrete composite buildings, where steel beams interact with concrete slabs through shear connectors. Numerical models of 2‐4 story regular frames are constructed, in which span (15‐25 m), story height (3‐4 m), and floor configuration (bare deck, 50% and 100% composite action) are varied. Loads include self‐weight, a unit gravity load of 1 kN/m2 per floor, and unit base accelerations (1 g) following the two orthogonal directions, to evaluate the influence main parameters on drift and displacement responses. Modal response‐spectrum analyses with the same code‐based spectrum are used to validate the unit‐load rankings. Selective pushover analyses of the most efficient configurations, using codified definitions are used to evaluate ductility capacity and hinge formation. It is indicated that composite action reduces drifts and improve stiffness‐to‐weight versus steel counterparts, supporting preliminary selection criteria for low‐ to mid‐rise buildings in seismic regions.