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The provisions to determine the deflection of gypsum wallboard (GWB) sheathed shearwalls available in the Canadian and American standards are limited to nailed shearwalls and are rudimentary compared to the wood based sheathing equations. There is currently no fastener slip model for the GWB sheathed shearwalls that are fastened with GWB screws. A main goal of this study is to improve the existing equations for nailed GWB sheathed shearwalls and develop a suitable analytical expression that can be used for GWB fastened with screws. In total, 270 GWB sheathed joints were subjected to reversed cyclic loading with variations including GWB type, thickness, fastener type, fastener size and manufacturers. The power model type is used to develop the fastener slip equations for nails and screws, which have GWB density and fastener diameter as equation inputs. The accuracy of the developed model is then validated by comparing the tested full-scale GWB sheathed shearwall deflection to the deflection calculated using the newly proposed fastener slip models. The proposed equation is a significant improvement to the existing code provisions. Component testing was performed on the fasteners (center point bending test) and the GWB (dowel bearing test). The results of these tests were used to determine the joint capacity based on the European Yield Model. It was also found that the shearwall capacity could be predicted by considering the joint level capacity while accounting for the number of joints at a panel edge. The joint level and full-scale experimental results are also validated with the use of an analysis program (SAPWood) to model the joint level hysteresis as a hysteretic spring with 10 model fitting parameters. The developed joint level hysteretic model was then used to represent the fasteners connecting the sheathing panels to the lumber framing in the construction of the full-scale shearwall model.

Master of Science / Department of Architectural Engineering / Kimberly Waggle Kramer / Main lateral force resisting systems (MLFRS) in timber buildings consist of two components: diaphragms and shear walls. Diaphragms are used to collect the shear induced by the lateral force at each of the levels. The shear is transferred from the diaphragms to the shear walls via plywood sheathing and connections. The shear walls transfer shear to the sill plate via plywood sheathing and then into the foundation via anchors. Two approaches for designing shear wall are: the segmented shear wall approach and the perforated shear wall approach. The segmented shear wall approach uses only full height segments to resist shear; each individual segment must be designed to resist the shear and overturning force induced by the lateral load. The perforated shear wall approach uses both full height segments and segments around openings to resist shear; the wall as a whole is used to resist shear and overturning forces induced by the lateral load. This report examines one-, two-, and three-story timber buildings located in three different wind regions: a) 115 mph, b) 140 mph, and c) 160 mph. This report presents the design process for the MLFRS components and a comparison of the designs for each of the buildings. The purpose of this report is to determine how the design changes depending on the magnitude of the lateral load, the height of the building, and the approach used to design the shear walls.

This study investigates the monotonic and cyclic response of light-frame wood shear walls with and without openings. Effects of overturning restraint in the form of tie-down anchors and corner segments on light-frame shear walls with and without door and window openings were quantified. While the results are useful to refine a design methodology for shear walls containing openings, they also provide important knowledge that is needed to accurately quantify anchorage requirements for shear wall design, and assess remaining load and ductility capacity of wood frame buildings after earthquakes or hurricanes. Sixteen full-scale wall specimens were tested using monotonic and sequential phased displacement (SPD) patterns. A total of five different wall configurations, five anchorage, and two loading conditions were used. All walls were eight feet (2.4m) high. Straight wall specimens were forty feet (12.2m) long, whereas corner walls measured twelve feet (3.7m) in length. The analysis includes data from a previous investigation in order to further expand the scope of this study. Results reveal that ultimate capacity and stiffness increase with increasing overturning restraint. A shift in failure mode was observed when overturning restraints were omitted. Accumulated damage experienced by the wall specimens tested cyclically was fairly uniform, regardless of the amount of overturning restraint or size of openings present. / Master of Science

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