Soil-structure interaction response considering drift analysis due to three orthogonal components of near-field ground motions

Soil-structure interaction analysis is one of the most challenging problems in the field of structural engineering. In this paper, two aspects less discussed in the literature, namely: (ⅰ) the effect of considering all three components of near-field earthquake excitations instead of just one horizontal component, and (ⅱ) elimination of the part of inter-story drifts caused by the foundation rocking, have been investigated. Theoretical aspects of both phenomena have been considered, and useful considerations have been proposed. To provide a more comprehensive description of the suggested modifications, the seismic behavior of a 15-story steel moment-resisting frame building subjected to four near-field earthquake excitations has been studied. To that end, 3D nonlinear time-history analysis was conducted using ABAQUS finite element software. The structure is supported by a shallow raft foundation on soft-clayey soil. The results indicate that the two mentioned points are of prime importance and should be considered in the soil-structure interaction analysis due to near-field excitations to evaluate the seismic structural responses more accurately.