Experimental and numerical research on hysteretic behavior of bolted end-plate connections

Abstract

To investigate the seismic performance of end-plate connection, two scaled-down specimens, Z1 and Z2, were designed and tested under cyclic loading. These tests examined failure modes, load-bearing capacity, stiffness, ductility, and energy dissipation. The Z1 specimen failed due to shear in the column web, while Z2 developed a plastic hinge at the beam's end, showing different failure modes. The seismic performance of these joints was excellent, exceeding current standards and offering high safety reserves. A parametric analysis using 20 finite element simulations assessed key factors affecting joint performance. Results showed that while the axial compression ratio minimally affects initial stiffness, higher ratios may cause earlier failures at ultimate strength, recommending a maximum ratio of 0.5. The thickness of end-plate stiffeners, bolt diameter, and bolt pre-tension significantly influent both initial rotational stiffness and ultimate capacity, with column stiffener thickness mainly affecting initial stiffness. A design formula for initial rotational stiffness, based on the European Standard EC-3 component method, was validated by finite element model results, confirming its accuracy.