Tensile Capacity of Single-Angle Shear Connections Considering Prying Action

The 2009 International Building Code (IBC) structural integrity provisions include a minimum tensile capacity requirement for simple shear steel connections. An all-bolted single-angle connection has been physically tested and analytically modeled to determine its ability to meet this code requirement. The single-angle connection studied was an ASTM-rated A36 $102\times 76.2\times 9.53\text{-}\text{mm} (\mathrm{L}4\times 3\times 3/8\text{-}\text{in.})$ connection having four A325 19.1-mm-diameter (0.75-in.-diameter) snug tight bolts on each angle leg. This connection’s tensile capacity, calculated by prying equations from the current AISC Steel Construction Manual, does not meet the new IBC requirement. Six full-scale tests were performed. For three tests, a lateral restraint was included to examine the effect of beam restraint on connection tensile capacity. The ultimate tensile failure load of the connection was observed to be three times the value predicted by the current AISC prying equations. Both tensile rupture of the web-framing angle leg and bolt tensile failure modes occurred. Presence of lateral restraint decreased the variability in tensile capacity. Finite-element analysis was performed to explore observed connection behavior. Results of the physical tests and computational analysis were used to make recommendations to modify the AISC prying equations to more accurately predict the tensile behavior of single-angle connections. The proposed equations use a plastic-hinge model to determine the effects of prying action on bolt strength for single-angle connections, accounting for their inherent flexibility. Using the proposed equations, the connection meets the IBC tensile requirement.