Superelastic viscous dampers for seismically resilient steel frame structures

摘要

This study proposes a passive control device based on superelastic behavior of shape memory alloys (SMAs) and investigates the device performance for improving response of steel frame structures subjected to multi-level seismic hazards. The device, named as Superelastic Viscous Damper (SVD), exhibits both re-centering and energy-dissipating capabilities and consists of SMA elements and a viscoelastic (VE) damper. SMA elements are mainly used as re-centering unit and the viscoelastic damper is employed as energy dissipation unit. The VE damper consists of two layers of VE material bonded with three steel plates. Energy is dissipated through the shear deformation of VE material. Each SMA element forms a continuous loop; wrapping the loops around the outer two plates improves compactness and efficiency. An analytical model of a three-story benchmark steel building with the installed SVDs is developed to determine the response of the structure under a ground motion input. A neuro-fuzzy model is used to capture nonlinear behavior of the SMA elements of the SVD. Nonlinear response history analyses are conducted at MCE level seismic hazard. A suite of 22 ground motion records is employed in dynamic analysis. Peak interstory drift, peak absolute floor acceleration, and residual story drift are selected as the primary demand parameters. Results shows that SVDs can effectively mitigate dynamic response of steel frame structures under strong ground motions and enhance their post-earthquake functionality.