Behaviour of FRP-confined compound concrete–filled circular thin steel tubes under axial compression
Junliang Zhao, Chenhao Xu, Linzhu Sun, Dongyan Wu
Abstract
This article presents test results of a recent study on the axial compressive behaviour of fibre-reinforced polymer–confined compound concrete–filled thin steel tubes. The usage of compound concrete, which is a mixture of fresh concrete and large pieces of recycled concrete lumps, can recycle waste concrete in a simple but effective way. Totally, three series of tests were conducted, with the parameters including the relative strength between fresh concrete and recycled concrete lumps, the volumetric percentage (i.e. mix ratio) of recycled concrete lumps, the diameter-to-thickness ratio of the steel tubes, and the thickness of the fibre-reinforced polymer jackets being investigated. The stress–strain curves of the steel tube and compound concrete core were derived and the effects of different parameters were then examined and discussed. An existing stress–strain curve model of fibre-reinforced polymer–confined normal concrete-filled steel tubes was also found performing well in predicting the behaviour of fibre-reinforced polymer–confined compound concrete-filled steel tubes.