Multihazard framework for investigating high‐rise base‐isolated buildings under earthquakes and long‐duration winds

Abstract

AbstractJapan experiences a considerable number of low to medium earthquake shocks and long‐duration winds throughout the year, which is relatively more as compared to other different regions of the world. Considering this multihazard scenario, structures designed using the existing guidelines may have significant chances to underestimate the induced distress level in the structure as well as in the energy dissipation devices, which are designed based on traditional peak variables neglecting accumulation of damage. To overcome the shortcoming of the existing assessment technique, a multihazard framework is formulated that deals in estimating probable number of earthquakes and long‐duration winds likely to occur in the design life of a structure. The sequence of design earthquakes and long‐duration winds obtained through the proposed methodology is subsequently implemented in base‐isolated high‐rise buildings of two different heights, which are designed based on Japanese standard. Responses are addressed in terms of displacement and acceleration at isolation and top floor level, force‐deformation and fatigue damage induced in the isolation devices under individual and multihazard scenarios. Results show that a particular range of building exists that is governed by both earthquake and wind events, and it is recommended that design of such building types should include the effects of both hazards. Moreover, the series of events likely to occur in design life of the buildings induce significant damage in the isolators as compared to the individual hazard event, thereby emphasizing a strong need to develop multihazard framework, where the occurrence rate of such extreme events is relatively higher.