Experimental Research On Concrete Short Columns Confined By Wire Rope Under Axial Compression

Concrete members strengthened by fiber reinforced polymer (FRP) is becoming an increasingly popular retrofit technique in recent years due to the excellent material properties, easiness of construction and sound strengthening effect of FRPs. However, there are still two important problems should be considered. On one hand, the bond deficient of resistance to elevated temperatures. Methods of fireproofing are needed. On the other hand, it is very expensive to use FRP, the economic indicator is lower than others. So it is urgency to find a strengthening method which is easy to construct, has a better effectiveness and higher economic indicator. The wire rope which is soft, high-strength and can be bought easily is used here. A good result is achieved by concrete short columns wound with thin wire rope in different intervals. This strengthening method has several merits such as bond is not used, easy to construct and high economic indicator. It is hoped that this method will be used in strengthening compressive members.Experiments were done on the 24 concrete short columns wound with wire rope with different cross sections (circle and ellipse modified from rectangle) and different wire rope interval. The influence of the difference on the bearing capacity of the columns is compared. The capability of this type of confined concrete subjected to axial compression is also researched. According to the load-carrying law of this kind of columns, the failure process can be divided into three working stages, namely, elastic stage, elastoplastic stage and strengthening stage, which is the inherent property of confined concrete by comparing with other confined concrete. The results indicated that the compressive strength and ductility of the columns are improved efficiently by the external confining wire rope. As the interval reducing, the compressive strength and ductility increase. Circular section is better than elliptical section.Based on the test results, an experiential formula of ultimate load-bearing capacity of columns with circular and elliptical cross-sections is carried out. And a unified mathematical expression for stress-strain relationship of short columns subjected to axil compression is proposed herein. In the proposed model, the...