Performance of steel angle connections at elevated temperatures

The performance of connections is crucial for maintaining stability of structural system during fire conditions. In current practice, no special consideration is given to account for various high temperature effects, including fire induced forces, on the behavior of connections. To overcome some of the drawbacks in current design provisions and to characterize the realistic behavior of double angle connections, a numerical study has been undertaken. As part of this study, a finite element model of beam to column double angle connection has been developed and validated against experimental results. The finite element model accounts for material nonlinearity, geometric nonlinearity and degradation of constitutive properties with increasing temperature along with non-linear contact interactions. The validated finite element model was applied to study the effect of bolt-hole size and beam web thickness on the performance of double angle connections. Results from the analysis indicate that higher bolt-hole size enhances flexibility of the connection. Also, the results show that higher web thickness leads to larger stiffness and load carrying capacity in the double angle connections.