Analysis On The Behavior Of Concrete-filled Rectangular Steel Tubular Stub Columns Under Axial Compression

Because the structure of concrete-filled steel tubular (CFST) can take advantages of the two kinds of material of steel pipe and concrete fully, nowadays, it has already been used widely in the engineering practice. But, the section shapes are mostly square and circular. Though the restriction effect of the steel tubular of concrete-filled rectangular steel tubular to core concrete is not as good as concrete-filled circular steel tubular, concrete-filled rectangular steel tubular has many advantages, such as easier to connection with beams, good ductility, good fire-resistance and so on, people has become to attach importance to it. The length and width of the section of the concrete-filled rectangular steel tubular are unequal, so that the restriction between the tubular and core concrete is complicated and it is difficult to deduce the limited carrying capacity in theory. If we ignore the restriction between the tubular and core concrete, the advantage of this structure will be deduced. Based on a great deal of experiments, and taken mostly influencing factors into account, I attempt to deduce the limited load-carrying capacity formula of the concrete-filled rectangular steel tubular column by the method of multiple linear regressions. This method provides a new idea for forecasting and evaluating the limited load-carrying capacity of the rectangular concrete-filled steel tubular. Furthermore, this method avoids complex process of mechanics analysis. Based on a great deal of experiments, the formula has some dependability.Based on the many experiments, the next part of this paper, using the powerful structure finite element analysis software ANSYS7.0, considering material non-linear and geometry non-linear question simultaneously, simulates the test of rectangular concrete-filled steel tubular short column under the axial pressure through reasonable modelings mesh and correct loading manner. And, deduce the limited bearing capacity of the experimental component. Furthermore, I summarize influence rule of bearing capacity's improvement be accompanying by ratio of length to width and restriction coefficient of experimental members. Besides, analyze experimental member's inherent mechanism and destroy mechanism. These accord with experiment results well. It istestified that the nonlinear finite element analysis method is correct and feasible.