Seismic collapse evaluation of steel moment resisting frames with superelastic viscous damper

Abstract

This study investigates the seismic collapse resistance of steel moment resisting frames equipped with superelastic viscous dampers (SVD) through incremental dynamic analysis (IDA). The SVD is a hybrid passive control device that strategically combines a viscoelastic device and shape memory alloy cables in parallel. The hybrid device exhibits improved re-centering and energy dissipating capabilities compared to only viscoelastic or only SMA-based devices. First, the design and mechanical behavior of SVDs are described. A nine-story steel frame building is selected for the numerical analyses. The building is first designed as a conventional special moment resisting frame (SMRF) to meet the strength and stiffness requirements of the design codes. Then, a reduced strength version of the fully code compliant frame is developed and upgraded with either SVDs or buckling restrained brace (BRB) system. Analytical models of the steel building for each configuration are developed to simulate global frame behavior by considering both geometric nonlinearities and cyclic strength and stiffness deterioration of structural steel components under dynamic loads. Incremental dynamic analysis is employed to assess the seismic resistance of steel frame structures up to collapse using 44 ground motion records. A sensitivity analysis is also performed to evaluate the influence of SVD design parameters on the seismic response of the frame. The results indicate that the steel frame designed with SVDs has the largest median collapse capacity and minimal residual drifts under various seismic hazard levels.