Experimental Investigation on the Seismic Performance of Assembled Trapeze Supports for Suspended Pipes

Although assembled trapeze supports are extensively employed in mechanical, electrical, and plumbing (MEP) systems, their seismic behavior remains scarcely documented in current literature. This study conducts monotonic and reversed cyclic loading tests on 15 representative configurations to systematically evaluate the hysteretic characteristics, failure modes, and seismic performance of assembled trapeze supports. Key design parameters including node connectors, channel steel specifications, diagonal bracing, and seismic hinge were specifically focused on. Through comprehensive analysis of envelope curves, characteristic displacement parameters, strength/stiffness degradation patterns, energy dissipation capacities, and critical strain distributions, the following findings were obtained: (1) Node connectors emerged as the most vulnerable components governing system failure. The interlocked connection specimens (ICS) demonstrated susceptibility to sliding and breaking at the nodes, whereas the bolted connection specimens (BCS) exhibited shear failure of bolt washers. (2) The BCS demonstrated superior elastic stiffness, bearing capacity, strength and stiffness degradation, and energy dissipation compared to the ICS. (3) Diagonal bracing significantly enhanced the seismic performance of the specimens. The seismic hinges, particularly the II-Type, were identified as critical components influencing this behavior, outperforming the I-Type hinges.