Force-displacement relations of bolted timber joints with slotted-in steel plates parallel to the grain

To study the force-displacement relations of bolted timber joints with slotted-in steel plates, we performed a monotonic loading test parallel to the grain on 24 specimens. The influences of the bolt diameter, timber thickness, and their ratio were considered. As shown by the test results, the joints had a high deformation capacity and experienced a linear stage, a stiffness degradation stage, a yield plateau stage, and a failure stage during loading. Based on the curve fitting and parameter identification, the force-displacement relations of the joints were summarized in a mechanical model with two parameters, i.e., the bearing capacity and the elastic stiffness. Based on theoretical analysis, we proposed a theoretical calculation formula for the bearing capacity and elastic stiffness of the joints. Finally, we calculated the force-displacement relation curves of bolted timber joints with slotted-in steel plates using the mechanical model and the theoretical formula. The calculated curves fitted well with the experimental curves.