Experimental Study On Shear Resistance Performance Of Concrete Filled Square Steel Tubular Columns

At present, concrete filled steel tube (CFST) is widely used in building structures such as factory building, super high-rise building and bridge structure. Generally, it's no need to design fixture for concrete filled steel tubular columns in shear resistance expressly. However, as the civil engineering is deep-going, people start to study the shearing performance of CFST for the problem of shear resistance which influence the design of concrete filled steel tubular elements.Aim at the gossamer field of research in shearing performance of CFST, this paper used experimental method and finite element analysis to study the mechanical performance of concrete filled square steel tubular columns under the action of shear force. Shear resistance tests of 6 concrete filled square steel tubular columns were made, which mainly discussed some parameters such as shear span ratio and axial compression ratio, and the damage shape, load-displacement curves and load-strain curves of specimens were presented from the experiment. At the same time, nonlinear finite element analysis using ABAQUS 6.5 was carried out to analyze the shearing performance of concrete filled square steel tubular specimens, and the computed result were compared with the test result to confirm the reliability of finite element analysis model.Based on the experimental study and finite element analysis, the shear resistance performance of concrete filled square steel tubular columns was analyzed in this paper deeply and systematically. According to the analysis of computed and experimental results, the influence of the connection length, loading area, bulkhead, shear span ratio and axial compression ratio was revealed, and the strain in the surface of steel was discussed, and the difference between shearing type damage and shearing-flexure type damage was compared. Make use of computed results, the calculation formula of relationship between shear span ratio and the shear bearing capacity of concrete filled square steel tubular columns with shear force was inferred. Considering the beneficial effects of axial compression on the shearing capacity, this paper established the calculation formula for the shear resistance of concrete filled square steel tubular columns, which consider the influence of the section size, strength of the material, shear span ratio and axial compression ratio. The compared result indicated that the formula computed result well conformed to the test result, and the result of calculating was safer than what the test gained.