In this paper, an optimization methodology proposed for the achievement of optimal (minimum) structural weight for flexible-base shear buildings under earthquake excitation. The underlying soil is considered as a homogeneous half-space which is replaced by a simplified 3-DOF system, based on the concept of Cone Models. Through intensive nonlinear dynamic analyses of buildings with consideration of soil-structure interaction (SSI) effect subjected to a group of artificial earthquakes, and using uniform distribution of inter-story ductility demand over the height of structures, an optimization procedure for seismic design of inelastic shear-buildings incorporating SSI effects is developed to achieve minimum structural weight. It is shown that the seismic performance of such a structure is superior to those designed by code-compliant seismic load pattern such that the optimized structures experience significantly less structural weight as compared with those designed based on ASCE/SEI 7-10 load pattern.
