Enhancing the seismic performance of mid-rise wood-frame buildings with rigid spine columns

摘要

Wood-frame buildings (WFBs) are the most commonly used structural systems for residential applications in North America. Past researches have shown that WFBs are susceptible to soft-story mechanisms. In this study, a simple, efficient, and economical retrofit strategy, which utilizes continuous pinned-supported rigid spine columns (RSCs) over the height of the building, is proposed. The retrofit aims to provide uniform deformation through the height of the building to prevent soft-story mechanisms. This retrofit strategy was applied to a six-story WFB located in Vancouver, British Columbia, Canada. A three-dimensional nonlinear finite element model of the prototype building was developed using OpenSees. A comprehensive parametric study was conducted to identify the most economical RSC design. Seismic performance of the prototype building, with and without the most economical RSC design, was assessed through extensive nonlinear time history analyses. Results showed that the proposed retrofit strategy can effectively improve the seismic behavior of WFBs to prevent soft-story mechanisms.