Effects of Vertical Load and Hold-Down Anchors on the Cyclic Response of Wood Framed Shear Walls

Twenty one $2.4\mathrm{m}$ by $2.4\mathrm{m}$ ( $8\mathrm{ft}$ by $8\mathrm{ft}$ ) wood framed shear walls were tested to study the effect of vertical load and hold-down anchors on the cyclic behavior of the wall. Seven different configurations were investigated including walls without hold-down anchors and uniform vertical loads of 0, 6, 12, and $25\mathrm{kN}∕\mathrm{m}$ (0, 425, 850, and $\mathrm{1,700}\mathrm{lb}∕\mathrm{ft}$ ) and walls with hold-down anchors and uniform vertical loads of 0, 12, and $25\mathrm{kN}∕\mathrm{m}$ (0, 850, and $\mathrm{1,700}\mathrm{lb}∕\mathrm{ft}$ ). The walls were loaded cyclically according to the Consortium of Universities for Research in Earthquake Engineering test protocol. Results show that the effects of vertical load on the cyclic response of wood frame shear walls are to: (1) increase the lateral stiffness and (2) increase the energy dissipation capacity. The lateral stiffness increased by up to 80% for walls with vertical loads of $25\mathrm{kN}∕\mathrm{m}$ $(\mathrm{1,700}\mathrm{lb}∕\mathrm{ft})$ , over the full range of displacement amplitudes; energy dissipation increased by up to 100% for walls with vertical loads of $25\mathrm{kN}∕\mathrm{m}$ $(\mathrm{1,700}\mathrm{lb}∕\mathrm{ft})$ , over the full range of displacement amplitudes. Results also show that hold-down anchors have minimal effect on the stiffness and energy dissipation capacity of shear walls when loaded to the design allowable load of $25\mathrm{kN}∕\mathrm{m}$ $(\mathrm{1,700}\mathrm{lb}∕\mathrm{ft})$ .