Behavior of the concrete filled FRP 'Can' under axial loading

Roof supports in underground mines have seen extensive development over last few decades. Concrete is one of the main materials used to construct the columns and this technology has seen substantial improvements and various innovations over the last two hundred years. The uses of concrete-filled tube (CFT) as column member become more popular in recent years due to various advantages such as increased capacity and stiffness as well as significant reduction in maintenance cost over reinforced concrete columns. Basically CFT referred to a tube filled with concrete fill. The tube acts as both longitudinal and transverse reinforcement to the concrete while providing confining pressure. Until recent years steel was used to construct the tube (‘can’) due to its favorable properties and availability. In recent years, increasing studies on the applications of fiber reinforced polymer (FRP) in structures have been reported. In line with this trend, a number of studies were reported on the use of FRP ‘can’ in such CFT members, particularly in mining applications. Such FRP ‘cans’ are preferred in mining application because of the portability due to its light weight compared to steel. This paper presents a brief review of the application of FRP ‘can’ in structural engineering and a preliminary experimental investigation in the behavior of a concrete filled FRP ‘can’ under axial loading. The compressive strength and failure modes of the FRP CFTs were obtained by varying the slenderness ratios of CFTs. The results are analyzed and discussed in terms of the effects of both slenderness ratio and lateral confinement due to the FRP ‘can’ on the stress state and therefore, on failure mode and strength behaviour.