Research On Axial Compression Performance Of Concrete Filled Double-Skin Steel Tubular With Hollow-Centered Square Section Short Columns

In the concrete-filled steel tube project,the outer and inner hollow interlayer structure combination form is used to give full play to the restriction of the outer steel tube on the sandwich concrete and the support effect of the inner steel tube on the sandwich concrete.It is superior to the mechanical properties of traditional concrete-filled steel tube structures.In order to ensure the application of concrete-filled double-skin steel tubular with hollow-centered square section structures in large-span and super high-rise complex buildings,improve the mechanical properties of the structure,and explore the bearing capacity potential,it is necessary to carry out a research on the axial compression properties of square hollow sandwich steel tube concrete.jobs.In this paper,based on the full research of domestic and foreign related literature,a complete set of test plans has been developed.Axial compression tests are carried out on 9 square hollow sandwich steel tube concrete short column specimens to study their axial pressure performance and analyze internal and external steel tubes.The influence of factors such as the proportion of steel used and the hollow ratio on the axial pressure performance and the establishment of the analysis model through the finite element software ABAQUS completed the nonlinear analysis work.The experimental study shows that the wavy buckling of the outer steel tube occurs after the specimen reaches the ultimate load-bearing capacity.The failure modes of the specimen are shear-type failure and waist-drum-shaped crimping failure.There is no cracking in the longitudinal welds of the steel pipe;the ultimate bearing capacity of the test piece increases with the increase of the steel volume of the outer steel pipe,and decreases with the increase of the hollowness.ABAQUS simulation analysis results show that the stress at the four corners of the outer steel pipe of the specimen is the largest,the inner and outer steel pipes produce large local buckling in the stress concentration area,and the axial stress distribution of the concrete is uniform;the failure shape and load of the specimen-The analysis results of displacement relation curve and limit load are basically consistent with the test structure.This paper takes the two parameters of the steel volume ratio and the hollow ratio of the internal and external steel pipes as the cut-in points,all the test pieces are taken with the same steel volume,the axial compression bearing capacity,the load-strain relationship curve and the load-displacement relationship curve are one by one The analysis provides a reference for the research and engineering application of square hollow sandwich concrete filled steel tubes.