Simplified inverse stiffness design for nonlinear soil amplification

An efficient stiffness design method for building structures is proposed in which nonlinear soil amplification and soil–structure interaction are taken into account in terms of equivalent linearization. A sway-rocking shear building model with appropriate ground impedances derived from both finite-element analysis and the equivalent linearization technique is used as a simplified design model and super-structure stiffnesses satisfying a desired stiffness performance condition are determined for a ground-surface response spectrum. The ground-surface response spectrum is transformed from the design response spectrum defined at the upper surface level of the engineering bedrock via the equivalent linearization technique and the one-dimensional wave propagation theory. In the process of the super-structure stiffness design, an improved and advanced inverse formulation is developed which regards the fundamental natural frequency of the interaction model as a principal design parameter. The reliability and accuracy of the proposed stiffness design method are examined by a two-dimensional finite-element model. Inelastic response characteristics of the so-designed model are also investigated.