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Abstract

This thesis reports on an experimental study on the earthquake/seismic resistance o f wood based shearwalls sheathed with oversized oriented strand board panels. This work extends from a previous study on walls subjected to quasi-static cyclic loading regimes by investigating the dynamic behaviour of this new wall system on a shake table. Monotonic, cyclic quasi-static and dynamic loading tests that included an applied dead load were performed on 2.44 m x 2.44 m shearwalls with standard (1.22 m x 2.44 m) and oversize (2.44 m x 2.44 m) oriented strand board panels. Measured and calculated properties for the 14 test walls are presented, which include the following: strength, stiffness and ductility values; energy dissipation values; and failure modes. This information was used to draw conclusions on the influence of panel size and panel-to-frame nail connection spacing on the behaviour of the shearwalls. Shearwalls constructed with single oversized panels (Type B) had an increase in capacity of 26% over regular walls (Type A) as measured by the maximum load reached in monotonic tests. Shearwalls constructed with single oversized panels and reduced nail spacing around the panel edges (Type C) had an increase in capacity of 104% over regular panel walls. The maximum loads measured in cyclic tests and the maximum base shears calculated in dynamic tests were in excellent agreement with the monotonic peak loads. In dynamic testing, the Type C walls were not significantly damaged when subjected to the same ground motion that brought the Types A and B walls to failure. The wall with the oversized panel and reduced nail spacing was subsequently failed when subjected to the same ground motion scaled to a higher peak ground acceleration. Single oversized panel walls with reduced nail spacing dissipated roughly twice as much energy compared to the other two wall types whether tested cyclically or dynamically. Nail withdrawal was the dominant failure mode in all test types. A newly developed, relatively short cyclic test protocol was successful in producing the failure modes compatible with the failure modes observed in dynamic tests.