Evaluating the effect of slotted bolted connections on the buckling performance and base shear capacity in steel braced frames

Slotted bolted connections present an innovative seismic detailing strategy for steel frames, enhancing energy dissipation via friction. By reducing brace force demand and connection damage, they offer a simple and economical solution for improved structural resilience. Their practical adoption remains limited due to insufficient research. This study evaluates the seismic performance of slotted bolted connections with varying slot lengths in steel braced frames subjected to different ground accelerations. The investigation employed FE simulations, calibrated against prior experimental data on slotted bolted connections. These properties were implemented in a verification portal frame, after which bracing was modelled using nonlinear springs in a representative steel frame subjected to different ground accelerations and slot lengths. Results demonstrate that, for the considered steel braced frame, increasing slot length from no-slip to 150 mm reduces brace buckling occurrences by 98% and 90% at peak ground accelerations of 0.10 g and 0.20 g, respectively. Correspondingly, base shears are reduced by 5.7% for peak ground accelerations up to 0.15 g and moderately reduced by 25.3% at 0.20 g. Thus, incorporating slotted bolted connections becomes increasingly effective in reducing base shear with increasing peak ground accelerations. While apex drift initially increases with slot length, it decreases over time under higher-magnitude seismic excitations.