椭圆形GFRP-混凝土-钢组合空心柱的轴压性能试验研究

The elliptical FRP-concrete-steel double-skin tubular column (elliptical DSTC) is a novel form of elliptical column which consists of an elliptical outer tube made of FRP, an inner tube made of steel, and an annular layer of concrete filled in between. Elliptical DSTCs have many advantages, such as light self-weight, excellent corrosion-resistance and exceptional seismic behavior, different bending stiffness around two axes of symmetry, which has a promising potential to be used as hollow bridge piers. Tests of elliptical DSTCs with elliptical steel tubes under axial compression were conducted. The effects of long axis to short axis ratio, FRP thickness and void area ratio were investigated. These specimens had a height of 600 mm, a long axis of 300mm, and different short axes (i.e., 150 mm, 200 mm, 250 mm, and 300 mm). Experimental results show: the concrete in elliptical DSTCs is well confined by the FRP tube and the steel tube, leading to excellent enhancement of strength and ductility; the peak stress of the confined concrete has a trend to increase with the increase of the long axis to short axis ratio; a larger void area ratio does not reduce the confinement effect of FRP tube and steel tube on concrete; the increase of FRP thickness would increase the ultimate stress and strain of confined concrete in elliptical DSTCs.