Hysteretic behaviors of square hollow column-truss beam-diagonal brace connections in steel buildings

This paper presents a novel square hollow column-truss beam connections incorporating diagonal braces, aimed at enabling accurate and efficient onsite assembly of modular, multi-story, and high-rise prefabricated steel structures. The hysteretic behavior of these connections was assessed through experimental study of ten cross-shaped specimens. Based on the experimental study, the load-displacement curve, ultimate bearing capacity, ductility and energy dissipation capacity were carefully examined. The test results show that with different combinations of critical components, three distinct failure modes including beam, column, and diagonal brace failure were demonstrated. For specimens without diagonal braces, the dominating failures were concentrated either on the beam or the column regions, and the hysteretic behavior of specimens with beam failure mode was superior than that of specimens with column failure mode. With incorporation of the diagonal braces in the connections, the failure region of specimens was shifted from the truss beam or the column to the braces, and the stiffness and load capacity of the connection were significantly improved. In addition, finite element model was established, and the accuracy of the numerical simulation results was verified by test results. Finally, based on the experimental and finite element analysis (FEA) results, the strategy for controlling the occurrence location and sequence of critical damage of such connections were proposed.