Experimental Study On Shear Performance Of Composite Column With High Strength Concrete Filled Steel Tube

Composite column with high strength concrete filled steel tube is based on the composite column with concrete filled steel tube core.In the composite column with high strength concrete filled steel tube,the precast high strength concrete filled steel tube core is applied in the middle of a traditional reinforced concrete column.Due to the existence of high strength concrete filled steel tube core,the vertical bearing capacity and the seismic performance of the columns can be enhanced and improved effectively,to meet the requirements of the buildings with high-rise and large-span.Thus,the composite column with high strength concrete filled steel tube has a promising future and a wide application prospect.According to a static test of 14 specimens,failure patterns and bearing capacities of the composite columns with high strength concrete filled steel tube were researched,and shear bearing capacity calculation formula was deduced and established.Meanwhile,the numerical simulation was completed.The shear performance of three reinforced concrete columns and eleven composite columns with high strength concrete filled steel tube were studied to analyze the effects of the size of the steel tube,aspect ratio,welding studs.In this thesis,the failure process,the failure characteristic,the propagation of cracks and shear bearing capacity were investigated in detail.The results show that the diagonal compression failure and shear-compression failure of the specimens would occurr.The shear capacities increased with increases of the dimensions of steel tube,and decreased with increases of aspect ratio.Welding studs was beneficial to improve the shear capacity but with limited room for increasing,meanwhile,the shear-bond failure was avoided in all specimens.For the specimens with shear-compression failure,the truss-baroclinic field was applied here to analyze the shear capacity of the composite column with high strengthconcrete filled steel tube except the contribution of the steel tube.The contribution of the steel tube was established according to Technical Specification for Steel Tube-Reinforced Concrete Column Structure.For the specimens with diagonal compression failure,the shear capacities could be obtained from the modified theory as fore mentioned.A calculation formula for composite columns with high strength concrete filled steel tube was established.Based on the experimental results and the existing specifications,a simplified calculation formula was proposed.The calculated results agreed well with test results.On the basis of the test results,composite columns with high strength concrete filled steel tube were simulated by ABAQUS software.The results agree well with the test results.Composite columns with high strength concrete filled steel tube of different steel tube size but in same steel ratio were analyzed.The results indicate that the shear bearing capacity of composite columns with high strength concrete filled steel tube was different under different shear span ratios.