Experimental Study On Seismic Behaviors Of Circular Steel Tube Composite Columns Filled With Steel Reinforced Concrete

As a kind of new structure, we have carried out six circular steel tube composite columns filled with steel reinforced concrete experiment of stub column under axial compression or eccentric compression. This paper is in the original study conducted on the basis of the dynamic properties of the structure, through the different axial compression ratio and the rate of steel specimens of the five, low frequency cyclic loading test study, and the experimental results with theoretical analysis, focusing on the seismic performance of the structure.In the pre-prepared on the basis of theory, details of the implementation of the idea of a pilot test , the production process of the columns, the loading equipment, the loading methods, and the data acquisition, then analysis of the test failure mechanism.By experiment carried out the looping curves and the skeleton curves under different axial compression ratios and different steel ratios, analyzed and compared stability bearing capacity in different axial compression ratios and different steel ratios. The results show that circular steel tube composite columns filled with steel reinforced concrete has a high bearing capacity, test results are flexural failure; the looping curves maintain good stability in different controlling factors and show that the looping curves of the columns are good, no draw shrinkage with good capacity of dissipating energy. From the skeleton curve find that steel ratio is good for the component bearing capacity, with the increase of steel ratio, columns have been significantly improved; In addition, the axial compression ratio on the skeleton curves and ductility components have significant impacts, on the axial compression ratio the higher the skeleton curves of the steep decline in the corresponding component ductility worse, the lower the better ductility components.Through tests analyzed and compared ductility and energy dissipation capacity in different axial compression ratios and different steel ratios. The results show that circular steel tube composite columns filled with steel reinforced concrete behaved very well, to increase the steel ratio or reduce the axial compression ratio is favorable to improve the element bearing capacity; with the increasing displacement energy dissipation capacity and equivalent viscous damping ratio are increased, that the energy dissipation capacity is growing, so it can effectively resist the role of the earthquake energy, and the energy dissipation capacity of the component is better with the axial compression ratio smaller and the steel ratio greater; to increase the steel ratio or reduce the axial compression ratio is favorable to delay the stiffness degradation; even in the high axial compression ratio axial compression ratio the circular steel tube composite column filled with steel reinforced concrete still meets the standard limit on the limiting displacement drift seismic requirements, the ductility is increased with the increase of the steel ratio, but decreased with the axial compression ratio increase.