Analysis And Experiment For Concrete- Filled Circular-Steel-Tube Short Columns Under Axial Load And Bond-Silpping

As a concrete-filled steel tube has many advantages, it gets more and more applications in engineering. The mechanical performance study of concrete-filled steel tube is one of the hot issues in the engineering study, but most of the research has focused on the capacity of research and the study of seismic behavior. Now the studies of concrete-filled steel tube cooperated work together and bond-slip performance lotion are limited both at home and abroad. Some of them are not deep enough. On the basis of the interactional study summary of the compounding mechanic perform and bond-slip performance of concrete-filled steel tube, The research items are as follows:(1)The concrete-filled steel tube columns load performance- slip curve have two forms, the first is a clear the peak point of curve and the subsequent decline, the second is without them, but obviously turning point. The interface bonding of the largest will change with the change of concrete column slenderness ratio, diameter- thickness ratio, the steel rate.(2)The interface bonding of the largest will changes with the change of concrete column slenderness ratio, diameter- thickness ratio, the steel rate. We derive change law of bond strength with the change of location and load by further analysis. We can know shearing force transfer length and bond-slip constitutive relations.(3) By two loading methods on concrete filled steel tube under axial loads of text. Mensurate non-line finite and stress-strain date analysis theoretical character comparison parameter, the axial bearing capacity of the columns increases as the longitudinal stress of the steel tube decreases. The results of elastic-plastic analysis of the steel tube indicate that the steel yields at the peak load. A design equation is proposed to calculate the axial bearing capacity of circular tube confined concrete columns.(4) Finally, the finite element analysis of two test units are given by using finite element software Ansys, which is based on the suitable stress-strain relationship and the criterion of failure of concrete and steel tube,and combination stress analysis issue built two groups'axial loads limit bearing capacity. At the same time, it shows that the mechanical characteristic of finite element model is equally to the theory analysis. The results from the proposed equation for stub columns are consistent with the test results.