Contribution of Type-X Gypsum Wall Board to the Racking Performance of Light-Frame Wood Shear Walls

This paper presents an experimental investigation of the racking performance of light-frame wood shear walls to evaluate the effect of Type X gypsum wall board (GWB). Twelve shear walls sheathed with oriented strand board (OSB) alone, GWB alone, or in combination were tested under static monotonic or reversed cyclic lateral load. The racking performance of these wall specimens in terms of stiffness, strength, ultimate displacement, ductility, energy dissipation, and failure modes was investigated. Specifically the effects of panel orientation, GWB panel joint taping, and double-layer GWB were examined. It was found that shear walls sheathed with GWB provide ductility ratios similar to or higher than those of OSB sheathed walls. The direct superposition rule can be applied to estimate the overall strength of a shear wall sheathed with single-layer OSB and GWB on opposite faces, provided there is no panel joint taping and the panel orientation is the same for both materials. The superposition rule proposed in current United States standards provides a conservative estimate for other cases considered in this study. In addition, shear walls with two GWB panels jointed by taping and double-layer GWB panels behaved like shear walls sheathed with a single large-size panel, leading to a reduction in the system ductility ratio and corresponding seismic force modification factor. This test series have provided essential test data for future modeling work to investigate the seismic response analysis of light wood-frame buildings containing Type X GWB. (C) 2016 American Society of Civil Engineers.