Seismic performance of buildings supported by a shallow doubly-curved shell raft foundation

Abstract

Foundation transmits loads of superstructure to soil layers. Also, seismic loads are transmitted to the superstructure via the foundation. It has been shown that the characteristics of the foundation affect the seismic response of the superstructure. The influence of shell foundations on the seismic performance of structures has not been investigated in the literature. In this paper, the seismic response of 5, 10, and 15-story steel moment-resisting structures supported by a shallow doubly-curved shell raft foundation is compared to the seismic response of these structures supported by a pile-raft foundation. It was assumed that structures are founded on soft-clayey soil. Soil-foundation-structure systems were analyzed under the influence of four earthquake excitations using fully nonlinear time-history analysis. The numerical results generally show that the maximum displacement decreases while the maximum shear force increases in each story of structures with shell foundation compared to structures with pile-raft foundation. Moreover, the results reveal the better seismic performance of structures supported by shell foundation in terms of the maximum inter-story drift compared to structures supported by pile-raft foundation.