Cyclic behavior and reinforcement of moment-resisting bolted glulam joints with cracks

This paper experimentally explored the influence of cracks on cyclic behavior of moment-resisting bolted glulam joints, and investigated the strengthening of self-tapping screws and friction dampers. Under reversed cyclic loading, the failure modes and hysteresis curves of pre-cracked specimens have been presented and analyzed in this paper. It was found that initial cracks not only led to the decrease in the moment capacity and elastic stiffness, but also impaired the ductility behavior and energy dissipated capacity of bolted glulam joints. The ductility ratio and accumulated energy dissipation can be reduced by 30% and 60%, respectively. With the installation of self-tapping screws and friction dampers, significant enhancement was observed in the above mentioned mechanical parameters of pre-cracked bolted joints. The elastic stiffness and energy dissipation are improved by 144% and 613%, respectively. Further, an analytical model is applied to calculate moment capacity of strengthened bolted joints and validated by experimental results.