Mechanical Properties of a Novel Plastic Hinge Seismic Fuse Based on Frictional Energy Dissipation to Avoid Brittle Failures in Beam-to-Column Moment-Resistant Joints

Traditional steel structure joints are prone to brittle failure under seismic excitation, and it is difficult to precisely control the location of the resulting plastic hinge or repair these joints after an earthquake. Therefore, based on the energy dissipation principle of the friction pendulum isolation bearing and automobile braking device, a low-cost friction-based plastic hinge (PH) joint is proposed to provide predictable energy dissipation and realize quickly repairable structures. The proposed PH was analysed theoretically, and five half-scale specimens using different bolt and friction materials were tested using cyclic reversing load. The test results showed that models PH-1 and PH-2 with Grade 4.8 and 8.8 limiting bolts, respectively, both provided a plastic rotation angle greater than 0.03 rad, exhibited experimental moment capacities of 0.91 and 0.93 times their theoretical capacities, and exhibited ductility coefficients of 2.75 and 3.14, respectively. It was found that high-strength limiting bolts were unsuitable as they damaged difficult-to-replace PH components. The selected PH configuration experienced damage to only the limiting bolts and friction plates and exhibited good plastic deformation capacity and hysteretic energy dissipation performance that met the plastic rotation, ductility, and friction energy dissipation requirements. Thus, the proposed PH can be used to improve the seismic performance of beam-to-column joints and the frames they form.