Wind design considerations for base-isolated post-disaster steel buildings in moderate seismic regions

This paper presents a performance-based design methodology applied to proportion post-disaster steel braced frame buildings equipped with base isolation under recurring winds and earthquakes. The case study is a 15-storey hospital steel braced-frame building located in Montreal, Canada, where both wind and earthquake loads are critical. The base isolation system is composed of 16 lead rubber bearings placed at the base of the braced frame columns and 29 friction sliders under the gravity columns. Finite element models of the fixed-base and base-isolated lateral force resisting systems that account for geometrical and material nonlinearities, are developed in OpenSees. The building models are subjected to a set of spectrum-compatible ground motions, as well as a set of wind time-history series that are generated randomly from wind tunnel data available at the Tokyo Polytechnic University aerodynamic database. Nonlinear wind and earthquake response history analyses provide estimates of the structural performance in terms of floor accelerations, interstorey drifts, residual drifts, and isolator shear demands at the linear and nonlinear-near collapse range. The findings demonstrate the effectiveness of base isolation to mitigate damage under lateral loads. The paper also reveals the need to integrate multiple hazards in design, relax the stringent service and strength wind criteria, account for the inherent system overstrength and allow for limited ductility in displacement-controlled members in wind design. • Performance-based design framework for tall, fixed-base and base-isolated buildings subject to strong ground motion and wind. • Dynamic assessment of the alongwind effects on tall, base-isolated post-disaster steel buildings in seismic regions. • Verification of the effectiveness of base isolation to mitigate wind-induced damage. • Investigation of the multi-hazard performance of tall base-isolated buildings under lateral loading of increasing intensity, • Evaluation of the margin of safety of base-isolated against the fixed-base post-disaster steel buildings.