Experimental and numerical study of mortise-tenon joints reinforced with innovative friction damper

A new friction damper is proposed for improving the cyclic response of mortise-tenon joints at multiple levels of seismic motion. In order to investigate the combined behavior of the proposed damper, quasi-static cyclic tests are conducted on five reinforced joints and one contrast joint made by Pinus sylvestris in strict accordance with the international test standard ISO-16670. Experimental results indicate that the smaller amount of tenon pullout, larger bearing capacity and initial stiffness, lower strength and stiffness degradation, and higher energy dissipation capacity simultaneously are exhibited in the reinforced joints. Increasing the friction coefficients of friction pads and the values of the clamping force helps to effectively improve the seismic performance of the mortise-tenon joints. The friction coefficient of 0.4 of the friction pads and the pre-tension strain of 0.03 in the bolt are considered as the optimal parameters to achieve the better reinforcement effect. High deformation capacities exist in the reinforced joints. A detailed finite element modeling approach is illustrated followed by the validation studies to obtain further insight into the mechanical behaviors of the reinforced connections described herein.

Automated summary

The new friction damper proposed in this study improves the seismic performance of mortise-tenon joints by reducing pullout, increasing bearing capacity and initial stiffness, minimizing strength and stiffness degradation, and enhancing energy dissipation capacity. Increasing the friction coefficients of friction pads and clamping force values can effectively enhance the seismic performance of the joints. Optimal parameters for reinforcement include a friction coefficient of 0.4 for friction pads and a pre-tension strain of 0.03 in the bolt. High deformation capacities are observed in the reinforced joints, and finite element modeling is used to further understand their mechanical behaviors.