Seismic performance enhancement of timber mortise and tenon joints using replaceable mild steel energy dissipation devices

• A novel soft steel energy dissipation and vibration reduction device has been developed to enhance the seismic performance of mortise and tenon joints in the wooden structures of historical buildings. • Conduct pseudo-static tests on mortise and tenon joint specimens with varying conditions of integrity and reinforcement. • The study involved a comparative analysis of failure modes, moment-rotation curves, stiffness degradation, energy dissipation capacity, withdrawal force, and ductility of the specimens. In civil engineering, mortise and tenon joints have long served as critical connection points in timber structures, particularly for their ability to absorb energy during seismic events. However, their inherent seismic resilience is limited. once compromised, their performance deteriorates significantly, necessitating timely reinforcement and protection. To address this challenge, a novel, removable, and replaceable mild steel energy dissipation device has been introduced. This device, which integrates steel collars and low-yield steel plates with the mortise and tenon joints using high-strength bolts, forms a cohesive assembly. During seismic activity, energy dissipation is achieved through the yielding of the steel plates, which can be conveniently replaced post-event by removing the bolts and installing new plates. Four joint specimens were tested to evaluate the seismic performance of timber mortise and tenon joints equipped with this additional replaceable energy dissipation device. The study involved a comparative analysis of failure modes, moment-rotation curves, stiffness degradation, energy dissipation capacity, withdrawal force, and ductility of the specimens. The study elucidated the effect of the novel mild steel energy dissipation device on the seismic performance of timber mortise and tenon joints. The results indicated that, in the absence of reinforcement, significant damage occurred to the wooden mortise and tenon joints, characterized by fibrotic wood grain and severe compression deformation of the beams and columns. In contrast, the timber joints equipped with the replaceable mild steel energy dissipation devices exhibited minimal damage during seismic testing, demonstrating enhanced structural resilience. The device effectively mitigates deformation and compression at the joint, enabling the structure to maintain a robust bearing capacity and stiffness after seismic events. Post-reinforcement, the specimens demonstrated fuller bending moment-angle curves, with improvements in bearing capacity, energy dissipation capacity, and deformation capacity by 35%, 15%, and 30%, respectively.