Reseach On Capacity Of GFRP-Concrete-Steel Double-Skin Tubular Columns

With the rapid development of all kinds of composite materials, a number of new types of composite structure emerged constantly. The application of FRP composite materials in civil engineering structural started late at home, but develops rapid and people already have a lot of scientific achievements. FRP tube-concrete-steel double-skin tubular column is a new form of combination column, it was recently proposed by Prof. J.G. Teng in The Hong Kong Polytechnic University. The column consists of an outer tube made of fiber-reinforced polymer, an inner tube made of steel, and the concrete between them. Because the test and theory research are not yet mature about this new type of combination column, this paper will make the following research:1. The axial compression test of GFRP tube-concrete-steel double-skin tubular columns.To study the mechanical behaviors and the failure modes about the GFRP tube-concrete-steel double-skin tubular columns under the axial compression, in view of the influencing factors such as the thickness of GFRP tube, the steel pipe radius-thickness ratio, the concrete section hollow ratio, the strength of concrete, this paper designed some DSTC axial compression short column specimen under various factors including GFRP pipe thickness, steel radius-thickness ratio, concrete section hollow ratio and strength of concrete. A total of8GFRP tub-concrete-steel double-skin tubular columns were tested under monotonic axial compression. In the experiment, failure process and phenomenon were recorded. According to the load-displacement and the load-strain curves, this paper analyzed how the thickness of GFRP tube, steel pipe radius-thickness ratio, the concrete section hollow ratio and the strength of concrete impact on the failure mode, ultimate bearing capacity and ductility properties.2. The numerical simulation research of the GFRP tube-concrete-steel double-skin tubular columns.On the basis of the test, the GFRP tube-concrete-steel double-skin tubular columns were made a numerical simulation research by using the finite element software ANSYS. Equivalent stress picture of the GFRP pipe, steel pipes and concrete are distilled, and also the corresponding displacement, the ultimate load. This paper plotted the load-displacement curve according to these graphs and tables. And at last, behaviors of these combination columns under axial compression are aggregate analyzed.