Experimental Study On Axially Compressed Concrete Stub Columns Confined By Different Materials

The carrying capacity of concrete under a tri-axial compressed stress grows greatly. Under a tri-axial stress state, the capacity of confinement goes up with the increase of the lateral compression. So it is an effective way to boost up the strength and ductility of concrete by confining the deformation in lateral orientation.The concrete-filled steel tube, which is one of the most frequently-used confined concrete columns, also has several disadvantages, including low resistance to corrosion and high cost of machining on steel tube. In order to improve these disadvantages, this paper tries to presents an investigation on concrete columns confined by PVC tube, polyethylene (PE) tube, carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP)-PVC tube,which have high resistance to corrosion and good ductibility.This paper presents an experimental investigation on axially compressed normal strength concrete columns,high-strength concrete columns and crumb rubber concrete columns confined by 9 different kinds of material, including steel tube, PVC tube, CFRP-PVC tube, GFRP-PVC tube, CFRP confinement, GFRP confinement, PE tube, CFRP confined PE tube, GFRP confined PE tube. Experimental phenomena during the testing and failure modes are depicted in details, and the force-strain curves, macro-scopical characters of deformation, failure mechanism and failure mode are studied in this paper. The ultimate bearing capacity of these 27 different concrete stub columns and the influence of confining materials on the ultimate bearing capacity are obtained. Experimental results show that the bearing capacity and ductility of concrete columns can be obviously improved through confinement. The advantage and disadvantage of these 27 different concrete stub columns are compared. The costs of these columns are estimated base on market prices in Guangzhou. The test results can benefit the construction engineering. The influence of concrete on mechanical property of confined concrete column is also presented.