Study on mechanical model of through-tenon joints in ancient timber structures

To study the M-θ mechanical model of through-tenon joints in ancient timber structures, a numerical model is established based on the analysis results of structural characteristics and mechanical mechanism of through-tenon joints. The numerical model is verified with the experimental data of through-tenon joints. The influences of joint gap, transverse elastic modulus of timber, and length of the large tenon on the bending capacity of the joint are analyzed. Based on the results of stress analysis, a three-fold multi-parameter M-θ mechanical model is proposed, with elastic point, yield point, and ultimate point as characteristic points. The mechanical model can be verified with the test results and applied to the stress analysis of timber frames. Results show that the through-tenon joints have good energy dissipation capacity and the joint deformation mainly occurs at the tenon. The bending capacity of the joint decreases with the gap between tenon and mortise. Increasing transverse elastic modulus of timber and large tenon length can improve the bending capacity of the joint to a certain extent. The M-θ mechanical model can well reflect the mechanical properties of through-tenon joints. Application of the mechanical model to a previous timber frame test indicates that a good match between the model and experimental results. This research can provide good reference for the maintenance and protection of ancient timber structures. © 2020, Editorial Office of China Civil Engineering Journal. All right reserved.