Seismic Performance of Mid-Rise Hybrid Light Wood Frame Buildings and Influence of Diaphragm Flexibility

Abstract

The structural response of mid-rise hybrid light wood frame buildings, incorporating portal frame and shear wall, under either cyclic load or earthquake action were investigated via finite element analysis. Based on the structural behaviour of the one- and five-storey hybrid buildings under cyclic loading, a method to estimate the ductility ratio, μ, and ductility-related force modification factor, Rd, for the light wood frame building containing two types of lateral load resisting systems exhibit different ductility characteristics was proposed. Four- and six-storey buildings with layouts that rely on shear wall only or a combination of shear wall and portal frame were designed using the Rd factors estimated from the proposed method. Natural frequency extraction and non-linear time history dynamic analyses were performed on these multi-storey hybrid buildings using a macro element model to represent the lateral resistant element in ABAQUS. The influence of horizontal diaphragm flexibility was considered in these analyses. The results show that the use of a Rd value higher than the lowest Rd factor of the two lateral load resisting systems suggested by the National Building Code of Canada may be justified.