Equivalent SDOF Models for Estimating Isolation-Layer Energy Dissipation in Base-Isolated Tall Buildings under Strong Winds

Abstract

An isolation layer composed of isolators and steel dampers in base-isolated tall buildings can dissipate wind-induced energy via repeated elasto-plastic deformation. Its energy dissipation can be used to estimate its wind-induced responses and the fatigue damage in the steel dampers. Computationally costly time history analyses using multi-degree-of-freedom (MDOF) models suggest that some structural parameters influence the isolation-layer energy dissipation. However, using common single-degree-of-freedom (CS) models cannot fully capture such influences (e.g., those caused by the damping ratio and the natural period of the upper structure). Hence, this paper proposes a more accurate new equivalent single-degree-of-freedom (ES) model to estimate the isolation-layer energy dissipation in base-isolated tall buildings under strong winds. The ES model considers the influence of structural parameters and uses the first mode shapes of the MDOF models. It is as computationally efficient as, but is more accurate than, the CS model. The results indicate that it can estimate the isolation-layer energy dissipation as closely as MDOF models of base-isolated tall-building under strong winds.