CYCLIC PERFORMANCE OF A VISCOELASTIC CONNECTION FOR USE IN WOOD-FRAME AND STEEL- FRAME GYPSUM SHEARWALLS

摘要

Conventional sheathing connections found in both wood-frame and steel-frame gypsum shear walls are inelastic, causing costly structural and non-structural damage during cyclic loading. An alternative to these conventional fasteners that improves the cyclic performance of the shear walls is presented. Rather than using intrusive mechanical devices for additional energy dissipation, a viscoelastic (VE) polymer was installed between the gypsum sheathing and the stud framing. The connections are tested under an industry accepted reversed cyclic load protocol at frequencies of 0.5 and 1.0 Hz. The experimental work demonstrated that the VE polymer improves energy dissipation for all connections. The gypsum-steel samples using VE dissipated 3.7 times more energy than the gypsum-steel specimens fastened with a drywall screw. Specimens with VE maintained their stiffness and energy dissipation capacity throughout cycles of constant displacement, whereas the conventional connections lost both stiffness and energy dissipation during these cycles. This new VE polymer connection will allow for non-structural materials such as gypsum wallboard to be considered as a structural element in design of both wood-frame and steel-frame construction in seismic and high-wind regions, while reducing the risk of costly damage.