Mechanical Properties Of Steel-encased Concrete Filled GFRP Tube Column Under Unidirectional Axial Compression

The fiber reinforced composites have the advantages of small modulus of elasticity,similar thermal expansion coefficient to concrete,convenient construction,high strength and good corrosion resistance.It can be used for a long time without durability problems in the corrosion environment,thus prolonging the service life of concrete structures and reducing the maintenance cost of buildings.A very broad application prospect is called "the third major structural material" after concrete and steel.However,because FRP itself belongs to linear elastic and brittle materials,brittle fracture is often occurred when FRP pipe concrete structure is applied.Bad ductility and weak energy dissipation capacity.In order to solve this problem and make full use of FRP pipe concrete structure,The advantages of Wang Lianguang,Northeastern University,put forward the GFRP tube-steel-concrete structure,which is a composite structure formed by a tube as a template,a built-in steel bone,and a concrete in a tube.Some achievements have been made in the study of mechanical properties of GFRP tubular steel concrete composite short columns,but there is a lack of research on long columns.The main contents of this paper are as follows:1.The finite element software ANSYS is used to establish the finite element model of the long column in the GFRP tube type steel concrete combination with the sample R-1.0 and R-1.5,and to verify the correctness of the selected constitutive relation,material unit and modeling method by comparing the ultimate bearing capacity,the load displacement curve and the deformation characteristics of the specimen.;2.The 32 GFRP tube type steel concrete composite long column finite element model was established.By analyzing the equivalent stress cloud map and load strain curve of different length and fineness ratio,different concrete strength grade,different steel ratio and different thickness of GFRP tube thickness,the above four factors were obtained in the GFRP tube type steel concrete combination.The influence law of the mechanical properties of the long column.3.The calculation model of GFRP tubular steel-concrete composite short column is introduced,and the accuracy of the calculation model is verified by the experimental data.By using the finite element simulation data,the stability coefficient of the long column of GFRP tube-steel-concrete composite long column is fitted,and the formula of axial compression bearing capacity of the combined long column is obtained.