Abstract:
To address the issue that the existing beam-column nodes of steel frames do not comprehensively consider earthquakes and continuous collapses, a new type of node with both seismic resistance and anti-collapse capabilities is developed. Cyclic loading tests were conducted for the double-hinge joints proposed in previous study. The test results show that the double-hinged joints have full and stable hysteresis curves. Their aseismic performance was significantly better than that of traditional welded joints, with an 18% increase in energy dissipation. Based on the test study, a double-hinged joint with multistage resistance was constructed. Specifically, a tie member was installed in the middle of the connecting region. It does not participate in the joint loading in the early stage but provides a strong axial tensile force in the later stage, thereby achieving the effect of multistage resistance. Employing the topology optimization method, rational construction measures for the tie region were proposed, thereby clarifying the configuration of the joint. After this, considering the multistage resistance, a simplified load-displacement relationship for the joint was established via theoretical analysis, enabling the quantitative calculation of the aseismic and anti-collapse performance. A simulation method validated by the tests was employed to analyze the aseismic and anti-collapse performance. The analysis results indicate that the gap at the end of the tie member significantly affects the joint performance. While fully utilizing the load-bearing capacity of the steel beam, the joint still retains the capability for recoverability after an earthquake.