Experimental Study On Stability Behavior Of FRP-Concrete-Steel Double-Skin Tubular Long Columns Subjected To Axial Compression

Fiber Reinforced Polymer (’FRP’for short)-Concrete-Steel Double-Skin Tubular Column (’Double-Skin Tubular Column’ or ’DSTC for short) is a new kind of hybrid columns which can make effective use of the characters of concrete, steel and FRP. This new hybrid columns has better mechanical properties than many other existing hybrid columns. This paper carries out the experimental study which researches the stability capacity of long DSTC subjected to axial compression, and does researches on the calculation formula of long DSTC.Firstly, this paper design and conduct the experimental study of long DSTC and short columns for comparison subjected to axial compression. The parameters studied include slenderness of DSTC and the diameter thickness ratio of inner steel tube. The production process of the columns is elaborated as well as the mechanical tests on the GFRP tube, seamless steel pipe and self-compacting concrete.Next, the experimental phenomena, failure modes and mechanical behavior of long DSTCs subjected to axial compression are discussed. The influence of the principal factors, such as slenderness, on the ultimate bearing capacity and ductility of DSTC is researched. As well as the physical parameters of DSTCs at the peak load is also studied.Then, taking the influence of the fixed effect of roller bearing into consideration, this paper calculate equivalent slenderness by the existing model with two arbitrary restrained ends subjected to axial compression. A formula of the equivalent slenderness ratio and stability coefficient is fitted. And the formula of the load-bearing capacity of long DSTC is proposed. Comparing the test results of this paper and related literature, the results show that the calculated value and the experimental value matches well.Finally, based on the existed calculation program of long DSTC subjected to eccentric compression, numerical simulation analysis is carried out of the test results of this paper and related literature. The results show that the calculated value and the experimental value matches well.