Experimental Investigation of the Effect of Vertical Load on the Capacity of Wood Shear Walls

A series of 10 tests were conducted to determine the effect of a vertical load on the lateral load capacity of wood frame shear walls. Static tests were performed on 2.4 m-by $\text{-}2.4\mathrm{m}$ wood walls, for varying vertical load. Tests were conducted with and without hold-down anchors. Specimens were subjected to three half cycles of lateral loading, the final being to failure. The presence of vertical load on a wood frame shear wall was found to have a significant effect on the lateral load capacity of the wall. The ultimate load capacities of walls with hold-down anchors increased by 20 and 28% for walls with a vertical load of 12 and $25\mathrm{kN}∕\mathrm{m}$ , respectively, as compared to the wall without vertical load. The vertical load was also found to have significant effect on the lateral stiffness of the wall. Results also show that hold-down anchors do not add significantly to the strength of the wall when a vertical load equal to the maximum allowable is present. Finally, the results presented suggest that current code specified allowable shear forces are conservative when a vertical load is present; the wall has additional reserve capacity than is reflected by current code specified allowable shears.