Nonlinear pushover analysis: assessment of a moment resisting steel frame

Abstract

The paper analyzes the response of a characteristic moment-resisting steel frame structure using the pushover method and investigates the effect of varying column cross-sectional dimensions on its seismic performance. The calculation is based on constructing the force- displacement relationship and determining the target displacement, which represents the maximum displacement at the top of the structure during an earthquake. The analysis involves simulating the behavior of a nonlinear mathematical model subjected to monotonically increasing horizontal forces and gravi-tational loads until the target displacement is reached. The system response at target displacement is compared with regulatory values to assess safety. Multiple frame models were analyzed to determine the maximum acceleration level at which the structure still meets regulatory requirements. The results indicate that a structure designed for a lower acceleration level can withstand stronger seismic forces, with some damage, and an adequate design approach can significantly influence the behavior of steel frame structures under earthquake action.