Integrating Viscoelastic Damping Elements for Enhanced Seismic Stability in Tall Steel Buildings Under Subduction Interface Earthquakes

This article presents a novel system designed to enhance seismic stability and post-earthquake resilience in tall steel buildings with an aim to ease the currently imposed stability-related height limitations on specific steel seismic force-resisting systems in high seismic regions. The system integrates conventional buckling-restrained steel braced frames in an inverted-V bracing configuration and incorporates vertically aligned viscoelastic damping elements at beam-brace intersections on each storey. This integration offers dual benefits: enhancing seismic performance by augmenting energy dissipation through supplemental damping and inducing secondary elastic storey shear stiffness to mitigate P-delta effects. This mitigates drift concentration along the height of the structure and reduces post-earthquake residual drifts. The adequacy of the proposed system is validated through nonlinear response history analyses conducted on prototype steel buildings of 10 and 20 storeys in Vancouver, BC, subjected to Crustal, In-Slab, and Subduction Interface seismic records. Residual and peak inter-storey drifts are monitored along building heights and compared with responses obtained using conventional design approaches, namely the strength amplification approach included in modern seismic codes while ignoring imposed height limitations. The analysis revealed that the conventional design method falls short in mitigating global instability under Subduction Interface records when ignoring associated height limitations. Conversely, the novel system’s dual benefits are demonstrated to deliver superior seismic performance by achieving a uniform drift distribution along building heights and residual drifts within prescribed post-earthquake repair limits.