Seismic Performance Testing of Partially and Fully Anchored Wood-frame Shear Walls

Earthquake performance of wood-frame shear walls was evaluated by comparing fully and partially anchored walls under monotonic, cyclic, and earthquake loads and comparing with code measures. Suitability of monotonic and cyclic testing to predict seismic performance was examined. Earthquake tests were conducted on 2440-mm-square walls with Douglas-fir studs. Two oriented strandboard panels were fastened to the frame with two gypsum wallboard panels on the opposite side. Partially anchored walls had two anchor bolts on the sill plate. Fully anchored walls had hold-downs at the ends. Four time histories were tested: three subduction zone ground motions and a strike-slip fault, all scaled to the Seattle design level. For fully anchored walls, subduction zone tests had capacities, energy dissipation, and failure modes most similar to cyclic tests. Wall displacement at maximum load was underestimated by cyclic and overestimated by monotonic tests. For partially anchored walls, subduction zone and strike-slip earthquake tests had capacity, displacement at maximum load, initial stiffness, and ductility most similar to cyclic tests. Energy dissipation was most similar to monotonic tests, and failure modes were consistent with monotonic and cyclic tests. Partially anchored walls had lower capacity, displacement at maximum load, energy dissipation, and stiffness as compared with fully anchored walls.