Experimental Research Of Bending Behavior For Composite Girders With Concrete Filled Rectangular Tubular Top-flanges

Steel concrete composite beam is a new type of composite beam structure, because of its excellent mechanical properties,concrete-filled steel tube composite girders stand out. Because of buckling of steel tube wall of composite girders are limited by concrete, local buckling strength is greatly improved, the strength of steel can be used to a greater extent; and the concrete is mainly filled in the compression zone of the beam, which is constrained by the wall of the steel tube,so it’s mechanical properties are improved, and the advantages of good compression performance are fully played. Moreover, the new composite beam also has the advantages of high strength, high rigidity, good ductility, convenient construction and so on.At present, the researches on concrete-filled steel tube composite girders in the world is still few, especially the rectangularcomposite Girders with Concrete Filled Tubular Up-flanges. In this paper, the experimental bending tests of rectangularcomposite girders with concrete filled tubular up-flanges in three kinds of different cross sections are studied, and the expansion parameters of the new composite beam are analyzed by using finite element ABAQUS,and the elastic-plastic bending capacity of the three kinds of composite beams are derived.the main works of this paper are listed as follows:1、The bending capacity experiments of three simply supported rectangular steel tube flange beams are finished which are applied concentrated forces on middle span. The failure mode, stress-strain relationship for section and load-displacement relationship for the top and bottom flanges of three different types of rectangular steel tube flange beams are analyzed and studied, and then, the ultimate bearing capacity of three specimens are got.2、The finite element model of each specimen was established by using ABAQUS finite element software, statically loaded under third-point bending the model of finite element that span load- displacement curve and the test curve are compared and validate the model correctness.3、Steel strength, concrete strength, section form, steel content and section height width ratio are considered, using ABAQUS finite element software to analyze the parameters of the specimen, and the influence of the parameters on the composite beam was studied.4、Based on the model test result sand the results of parametric analysis, the paper puts forward a proposal for the design of a new type of new composite girders with three different cross sections.