Slope topographic impacts on the nonlinear seismic analysis of soil-foundation-structure interaction for similar MRF buildings

Abstract

Seismic waves reflected from slope surface amplify ground surface motions in the area near the crest. Therefore, the seismic response of structures considering seismic topography-soil-structure interaction (TSSI) is different from their response considering soil-structure interaction (SSI). This paper investigates the seismic performance of three groups of moments resistant frame (MRF) steel structures with 5, 10, and 15 stories through the three-dimensional (3D) numerical simulations. In each case of TSSI, these buildings with similar dynamic characteristics are modeled simultaneously at various distances from the crest. The inelastic performance of MRF components was simulated using the plastic hinges. Also, the nonlinear soil performance was considered by a hardening elasto-plastic hysteretic model, i.e., the constitutive model of the hardening soil with small-strain stiffness (HSsmall). Results show that the topographic irregularities magnify the acceleration at a distance of 2–3 times the slope height (H) from the slope crest. Moreover, the greatest impact of topography on the seismic responses is found for the building near the slope crest. Results also demonstrate the seismic response of 5-storey buildings is very little affected by slope topography. On the other hand, slope topography significantly intensifies the seismic responses of 10 and 15-storey buildings. According to the TSSI analysis, the maximum lateral displacements of 10 and 15-storey buildings are increased by 10%–125% compared to the SSI analysis. Besides, maximum base shear forces for both buildings increased more than three times.