Midply Truss Wall System: High-Performance Shear Wall for Midrise Wood-Frame Buildings

A high-performance wood-frame shear wall system, named the MIDPLY truss wall (MTW), was developed for application to midrise wood-frame buildings. The basic MTW system consists of metal-plate-connected wood trusses, sheathing panels, and steel tie-downs. The sheathing panels of the MTW system are placed between the wood trusses and connected with mechanical fasteners. The main concept of the MTW system is to increase the lateral load resistance of a shear wall by reconfiguring the wall frame members into lateral load-resisting wood trusses. In this study, the feasibility of the MTW system was investigated. Eight 2,440 3 2,440 mm MTW walls were constructed and tested under monotonic and cyclic loading in accordance with ASTM test standards. Shear stiffness, strength properties, and ductility of the MTW walls were evaluated and compared with those of comparable MIDPLY walls. Overall, the MTW system shows significant improvements in shear stiffness, yield load, peak load, and ductility. This paper contains a discussion of the failure modes, the effect of the vertical load, the importance of truss design, and the further studies needed. DOI: 10.1061/(ASCE)ST.1943-541X.0000536. (C) 2012 American Society of Civil Engineers.