Experimental Research On Seismic Behavior Of Rectangular Concrete-filled Steel Tubular Stub Columns With Binding Bars

As a new type of structural components, concrete-filled steel tubular(CFT) column with binding bars shows good mechanical properties. It has been gradually applied in engineering practice, and has achieved good effect. However, the current research on the CFT column with binding bars mainly focuses on the static performance, the seismic performance is rarely reported. Therefore, based on the existing research on the static performance, experimental study and theoretical analysis on the seismic performance of rectangular CFT stub column with binding bars is carried out in this paper. The main research work is summarized as follows:(1) Quasi-static tests on four specimens of rectangular CFT stub columns without binding bars and eleven specimens with binding bars are carried out. The main experimental parameters are the axial load ratio, the spacing of binding bars and the length-width ratio of specimen crosssection. The effects of varying parameters on the behavior of specimens such as hysteretic curve, skeleton curve, stiffness degradation curve, bearing capacity, deformation capacity and energy dissipation capacity are analyzed. Experimental results indicate that the rectangular CFT stub columns with binding bars have good bearing capacity, deformation capacity and energy dissipation capacity, and they have better seismic performance than those without binding bars.(2) Utilizing the finite element software ABAQUS to imitate the rectangular CFT stub column with binding bars. By contrast we can find the calculation results agree well with the test load-displacement curves. And on this basis the analysis of the rectangular CFT stub column with binding bars throughout loading history is carried out.(3) Based on the ABAQUS finite element model, calculating and analyzing the effects of axial load ratio, concrete strength, steel tube yield strength, steel tube wall thickness, spacing of binding bars, diameter of binding bars and length-width ratio of specimen cross-section on the load-displacement curve of rectangular CFT stub column with binding bars.(4) Base on regression analysis of quasi-static test results, a trilinear restoring force model of rectangular CFT stub column with binding bars is proposed, which mainly investigates the effects of axial load ratio, spacing of binding bars and length-width ratio of specimen crosssection. By contrast we find the calculation results agree well with the test skeleton curves. And on this basis, the hysteretic rule of rectangular stub CFT column with binding bars under cyclic lateral load is summarized.