Investigation of Cyclic-Shear Behavior of Circular-Reinforced Concrete-Filled Steel Tubes

Abstract

The cyclic-shear behavior of composite circular concrete-filled steel tubes (CFSTs) and reinforced concrete-filled steel tubes (RCFSTs) was experimentally and numerically investigated. Specimens with 32.39 and 40.64 cm diameters were considered, with diameter-to-thickness ratios of 51 and 64, respectively. The effects of longitudinal and transverse reinforcement were experimentally studied. The experimentally obtained strength values were compared to those from existing shear strength equations. Experimental results showed that the presence of an internal reinforcement doesn’t significantly impact the shear strength of RCFSTs. All specimens exhibited some amount of ductility under cyclic shear but not necessarily to the extent that would make it a preferred ductile mechanism. The mechanics governing the shear behavior of the CFSTs were studied using validated finite-element models. It was observed that a compression strut develops in the concrete under shear deformations. This strut also contributed to the shear strength of the composite CFSTs.