Seismic Performance of Assembled Beam–Column Connections with Modified Reactive Powder Concrete under Different Steel Fiber Types in the Critical Cast-in-Place Regions

Abstract

Reactive powder concrete (RPC) and reinforcements have ultra-high bonding strength and, thus, a potential advantage in improving the connection performance of assembled structures. In this study, four assembled beam–column connections using modified reactive powder concrete (MRPC) under different steel fiber types in critical cast-in-place regions, as well as a monolithic concrete beam–column connection, were tested under low-cyclic loading. The results show that MRPC application in critical cast-in-place region connections significantly improved damage tolerance capacity and load-carrying capacity. End-bent short steel fibers had the most significant crack-resistance effect. Using end-bent long fibers could improve an assembled connection’s ductility by 102%. Straight steel fibers were easily pulled out and had the least inhibitory effect on cracks. Connections using wavy steel fiber had the lowest initial stiffness and shear capacity but the highest energy dissipation capacity. Using 30 mm end-bent steel fiber is recommended for comprehensive seismic performance. The Chinese code overestimated MRPC’s shear contribution. MRPC assembled connections’ crack capacity and shear capacity models were established.