Improved design and safety of shear plate and slotted tube connections

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The proposed research project is directed towards improving the current design and detailing provisions in Canada for structural steel connections. ADF Group Inc., representing steel fabricators in this country, and their engineers (DPHV) have expressed concern with respect to the existing design procedures and potential performance of shear tab beam connections. Similarly, a more cost effective and ductile configuration, as well as corresponding design approach, is sought for slotted HSS brace connections. Shear tabs are commonly used throughout Canada to connect structural steel beams to column or girder members. The current design procedure recommended by the Canadian Institute of Steel Construction (CISC, 2006) is limited to relatively small configurations with a single row of bolts. The design procedure does not address the use of multiple rows of bolts, heavily loaded connections, extended shear plate connections, combined axial and shear forces in the connection, nor the typical weld retrofit measures taken when bolt holes do not align. Slotted HSS brace connections are prone to fracture under the repeated inelastic cyclic deformations associated with seismic loading. At present, in order to account for this failure mode fabricators must reinforce these connections, which adds significant cost. A revised connection is needed that provides for enhanced inelastic performance without reinforcement. The overall objective of this proposed research project is to develop improved design and detailing guidelines for shear tabs and slotted HSS connections. This will be achieved through the completion of an extensive program of tests, finite element analyses and design evaluation. With this information the steel industry in general, fabricators and engineers such as DPHV will be able to more accurately and cost effectively design and construct shear tab and slotted HSS connections. This will place ADF and the steel industry in an advantageous position compared with competing structural materials. Ultimately, the improved design procedures and level of performance of these connections will be of benefit with respect to the safety of building occupants and owners.