Experimental Study On Mechanical Properties Of Short Corrugated Steel Tube Filled With Rubberzied Concrete Under Axial Load

Concrete-filled steel tube(CFST)have been widely used at home and abroad for their good mechanical properties and economic benefits.In recent years,with the continuous expansion of its application fields,the external environment of CFST becomes more and more complex,making the active energy consumption of the structure more and more important.The current energy consumption have many problems such as difficult construction and high maintenance cost.In order to solve this problem of CFST,based on the existing research results of CFST,rubberized concrete and corrugated steel tube,normal-and rubberized-concrete are poured into corrugated steel tube to form a new type of concrete-filled steel tube structure,named corrugated steel tube filled with concrete.In the corrugated steel tube filled with concrete structures,the active energy dissipation capacity of the structure is improved due to the incorporation of rubber particles in concrete.Corrugated steel tube can provide sufficient restraint to the rubberized concrete,effectively offset the disadvantage of low compressive bearing capacity of rubberized concrete.In this paper,the axial compression performance of concrete filled corrugated steel tube short columns are tested and ABAQUS finite element analysis is carried out.The main contents include the following aspects:(1)The test of fifteen short columns axial load have been completed,including five circular steel tubes,seven corrugated steel tubes,and three helix corrugated steel tubes filled with ordinary concrete and rubberized concrete.The experimental phenomena of specimens were observed and recorded in the test.The effects of steel tube forms,bearing mode,diameter-to thickness and rubber particle content on its mechanical properties under axial load were analyzed.The analysis shows that the corrugated steel tube has the best restraining effect on the core concrete;the diameter-to thickness is an important index affecting the performance of the test specimens;the rubber particles can make the test specimens have good ductile performance.(2)According to the experimental process,the transverse deformation of the specimens and the circumferential strain and longitudinal strain datas of the outer steel tube surface were obtained.Using the obtained strain data,the elastoplastic analysis of circular steel tube,corrugated steel tube and helix corrugated steel tube was carried out.The trend of stress variation on the surface of steel tube and the bearing capacity distribution of steel tube and concrete in the test piece were analyzed.The mechanism under the axial load of concrete filled circular steel tube,corrugated steel tube and helix corrugated steel tube were deeply understood.(3)A sea of analysis works have been done on the constitutive relationship between CFST and FRP-constrained concrete.Combined with the experimental data,different constitutive relations are proposed for the constraint form of circular steel tube and corrugated steel tube,and the nonlinear finite element software ABAQUS calculation is carried out.And the axial load properties of rubberied concrete specimens were simulated using the definition of key parameters of rubberied concrete.The surface stress and load-longitudinal strain curves of the steel tube obtained by finite element calculation are compared with the experimental data.The agreement between the two is quite good,which indicates that the constitutive relation and analysis method of the model can be used in the axial compression study of the specimen.(4)Based on the superposition principle of bearing capacity,the calculation method of ultimate bearing capacity of specimens under different steel pipe structures is put forward by comparing the test results with those of several representative codes..