Local Stability And Cross-Section Bearing Capacity Test And Theory Research Of Concrete Filled High Strength T-Shaped Columns

In recent years,high-strength concrete filled steel tubular columns can be widely used in various building structures and bridges due to their good mechanical properties and workability.However,due to the application of high-strength steel,the thickness of the pipe wall is reduced,so there is a greater probability of causing local buckling of the steel plate.This paper presents a new type of concrete-filled steel tube column—the steel plate with the wider side of the T-shaped column is set as a corrugated plate,which increases its bending stiffness,effectively delays the local buckling of the steel plate,improves the bearing capacity of the column,and makes it give full play to mechanical properties of itself.The mechanics of high-strength corrugated T-shaped concrete-filled steel tubular columns are studied,including the buckling theory of corrugated plates,experimental research and theoretical analysis of mechanical properties of T-shaped columns under axial force.The following three aspects have been carried out:1.Derived the unilateral restricted elastic buckling bearing capacity formula of corrugated steel plate,and verified it by ABAQUS finite element simulation;combined with the formula,the theoretical analysis of the optimal waveform structure was provided to provide a reference for the design of the experimental scheme.2.The axial compression test of 5 T-shaped steel tubular short columns was carried out,and the load-displacement relationship curves of ordinary T-shaped hollow steel tubular short columns and corrugated hollow steel tube axial short columns were obtained;two types of T-shaped steel tubular concrete columns were observed and analyzed.The influence of corrugated steel plates on the mechanical properties of T-shaped concrete-filled steel tubular columns was studied.The axial compression test of 6 T-shaped concrete-filled steel tubular short columns was carried out,and the load-displacement relationship curves of ordinary T-shaped concrete-filled steel tubular short columns and corrugated concrete-filled steel tubular short columns were obtained;two types of T-shapes were observed and analyzed.The influence of corrugated steel plates on the mechanical properties of T-shaped columns was studied.The test results was compared with the calculation results of formula in Nation specification,and the applicability of specification was inspected.3.The finite element models of T-shaped hollow steel tube columns and concrete-filled steel tubular columns were established by ABAQUS.Based on the experimental results,the correctness of the mode was verified,and the working mechanism of T-shaped concrete-filled steel tubular columns was studied.4.Based on a systemic parametric analyses including depth-to-thickness ratio steel tube,steel yield strength and concrete strength by ABAQUS software;study the compatibility of steel and concrete materials for CFST columns with thick or slender steel plate;a simplified bearing capacity formulation of the T-shaped concrete-filled steel tubular stub subjected to axial load was proposed by regression analysis.