The racking performance of shear walls with various aspect ratios. Part I. Monotonic tests of fully anchored walls

Current design values for light-frame timber shear walls are based on results of standard monotonic tests of 2.4-m (8-ft.) square walls restrained against overturning. The shear resistance of walls is calculated in terms of load per unit length, assuming that shear forces are distributed uniformly throughout the wall of any size. In past earthquakes, structural failures occurred near large openings where the lateral forces were transmitted through narrow wall segments. To improve our understanding of shear wall racking performance and to facilitate further development of seismic design methodology, a comprehensive study has been conducted that combines experimental and numerical analyses of shear walls of various configurations. This study included static monotonic and cyclic tests of full-size shear walls with height-to-length ratios of 4:1, 2:1, 1:1, and 2:3. Discussed in this paper is the static monotonic response of shear walls with overturning restraint representative of segmented wall construction practices. These walls were attached to the foundation by means of hold-down anchors and shear bolts. Test results revealed that the performance of segmented walls did not depend on the aspect ratio with the exception of narrow (4:1) walls, which exhibited 50 percent lower stiffness per unit length relative to the other walls tested. Differences in failure patterns and reduction in deformation capacity were observed when low-density studs were used at the wall ends. Traditional methods of analyzing segmented shear walls with hold-down anchors were shown to be sufficiently conservative.