Performance Of Wood Shear Walls With Big Openings

Wood shear walls provide the majority of the lateral force resistance in light-frame wood constructions,which makes up the vast percentage of residential and some percentage of commercial constructions in North America and other areas because of its good energy saving and seismic performance. Light wood-frame structure has currently been developed in China. The purposes of the wood-frame shear wall tests are to promote the application of light wood-frame structures in China and to provide scientific background for the revision of China's wood design codes.The performance of wood shear walls with big openings was the research subject of this thesis. Five shear walls containing two control wall with no openings and three shear walls with big openings were built. The lumber and sheathing are imported materials, and nails are made in China. Articulated segmental steel beam is used to transfer load instead of the whole steel beam. It can reduce the restriction of the top plate's deformation and simulate the worst condition. All walls did not contain tie-down anchorage at the extreme ends of the wall, which are respectively conducted under monotonic and cyclic tests and the effect of openings, vertical load and stiffness of upper floor change on the strength, stiffness, ultimate displacement, stud lift and energy dissipation of shear walls were studied.This paper presents a wood-frame shear wall testing program including design and fabrication of specimens, setup of testing frame and apparatus and the selection of load protocols. Test results and failure modes under monotonic and cyclic loads are also provided. The results show that: 1) the load-displacement envelope curves of the cyclic tests are similar to that of the monotonic tests; 2) the failure modes of the shear walls are mainly the failure of nail connections and the uplift of end studs; 3) the vertical load applied on the top of shear walls can dramatically improve the structural performances of shear walls.Also, this paper used three methods are used to predict the capacity of shear walls with openings. In this paper, predictions of the behaviors of five shear walls are presented and compared with the corresponding test results to evaluate their validity. Then modification factor will be proposed in order to consummate the China's wood design codes. In this thesis project, SAP2000software is used in the shear walls modeling. To efficiently predict the shear wall behavior through mathematical modeling, the properties of sheathing-to-lumber framing and lumber-lumber framing nail connections should be measured accurately using component material from the shear walls, whose behavior is being considered.The wood shear wall test of this paper is the first batch test in China. The research conclusions of this paper are very useful for developing wood structure buildings in China.