Experimental Research On Non-uniform Torsional Mechanical Properties Of I-shaped Beams With Rectangular Concrete-filled Steel Tubular Flange

With the development of civil engineering structure along the direction of large span,high rise,complication as well as convenient and fast construction,the existing building materials also need to be developed and optimized to meet the construction requirements of modern engineering structure.Although the traditional I-shaped steel beams have the advantages of high strength and light weight,it is often not easy to exert its advantage of high strength because of its lack of stability.As a result,I-shaped beams with steel tubular flange are proposed.The beams are formed by replacing the upper or lower flange of the traditional I-shaped steel beams with steel tube with a variety of cross-section,Such as translating the upper and lower flanges into triangular steel tubes,changing the top flange into rectangular steel tube or turning the upper and lower flanges into rectangular steel tubes and so on.As the original flange plate is changed into the closed steel tubular flange,the torsional stiffness of entire structure has been significantly improved,and the mechanical properties of the beam are more excellent.This study is about a new type of I-shaped beams with rectangular concrete-filled steel tubular flange.By injecting concrete into the rectangular steel tube,the shortcomings that I-shaped steel beams with steel tube is prone to local buckling are ameliorated,and the mechanical properties of the members are further improved.Due to the complexity of its cross-sectional form and the special requirements of its torsion test for the boundary conditions and loading,there is no relevant non-uniform torsion test now.Therefore,this paper analyzes the non-uniform torsional mechanical properties of single-span I-shaped beams with rectangular concrete-filled steel tubular flange by the method of experimental and finite element analysis.The main contents are as follows.(1)The mechanical performance test of three I-shaped beams with rectangular concrete-filled steel tubular flange subjected to non-uniform torsional deformation was carried out.In addition,a set of test devices for simulating the clamp support and the application of torque was designed for this test and a I-shaped beam non-uniform torsion test was carried out to initially verify the test devices.(2)The test phenomena and test data of three test beams are recorded in detail,and the relationship curves between load and strain as well as torsion angle and torque are plotted.The experimental results are analyzed to reveal the mechanical properties of the I-shaped beams with rectangular concrete-filled steel tubular top flange subjected to non-uniform torsional deformation.(3)Based on ANSYS finite element software,the finite element model of I-shaped beams with rectangular concrete-filled steel tubular flange was established,and its correctness was verified.The analysis of the non-uniform torsional deformation for the finite element model is carried out,and the results are compared with that of the experiment.Based on the finite element model,the effects of steel tubular flange aspect ratio,concrete strength and steel strength on the mechanical properties of I-shaped beams with rectangular concrete-filled steel tubular flange under the non-uniform torsional deformation are analyzed.