Seismic Responses in Isolated Steel Structures for Near and Far-Field Accelerograms

Abstract

Seismic responses of fixed-base and isolated steel structures were compared using near and far-field accelerograms. Accordingly, four, eight, and twelve-story steel structure models were created in SAP2000 for a time history analysis. Seismic responses, including relative floor displacement, base shear, potential energy, and plastic hinges were also considered for evaluation.

The results showed that seismic isolators reduced the seismic responses of far-field excitation by 80, 60, and 45% in the four, eight, and twelve-story buildings, respectively. However, near-field results were drastically different. Using the TABAS earthquake record on the eight-story building increased seismic responses by 25% on average. Moreover, some accelerograms showed seismic isolators to be ineffective in mitigating seismic responses of the twelve-story building.