Seismic Performance Assessment of Steel Frames Upgraded with Self-Centering Viscous Dampers

This study aims to evaluate the seismic performance of steel frames upgraded with shape memory alloy (SMA)based self-centering viscous dampers. The proposed Superelastic Viscous Damper (SVD) relies on SMA elements for recentering capability and employs viscoelastic (VE) damper that consists of two layers of a high damped (HD) blended butyl elastomer compound to augment its energy dissipation capacity. First, experimental tests are conducted to characterize behavior of SMA elements and VE damper and to assess the influence of various parameters such as displacement amplitude and loading frequency on their mechanical response. A prototype of the SVD is designed and fabricated. Then, an analytical model of a four-story steel special moment frame building with the installed SVDs is developed to determine the dynamic response of the structure. The incremental dynamic analysis is used to evaluate the behavior of controlled and uncontrolled buildings under 18 different ground motion records. The analytical results indicate that the buildings upgraded with the proposed passive control device effectively mitigate the peak interstory drifts and residual story drifts.