Research On Flexural Capacity Of Cold-formed Thin-wall Steel Truss Floor Composite With Lightweight Mortar* Specially : Architacture And Civil Engineering

Cold-formed thin-wall steel truss floor composite with lightweight mortar is a new kind of composite floor. lightweight mortar is sprayed between the cold-formed thin-walled steel truss. And a certain thickness of self-leveling mortar is poured on the topping. This new type composite floor has better performance of thermal insulation, sound insulation. and integrity than traditional cold-formed thin-wall steel composite floor.Through the full-scale tests of one cold-formed thin-wall steel truss floor composite with OSB panels and two cold-formed thin-wall steel truss floor composite with lightweight mortar studying under monotone static loads, the failure process, the bearing capacity and the failure mode were obtained. The results show that cold-formed thin-wall steel truss floor composite with lightweight mortar bearing capacity is relatively higher and the deformation is more small when compared with cold-formed thin-wall steel truss floor composite with OSB panels.Considering the material, geometry, and contract nonlinearity, the results of experiments were simulated with FEM using program ANSYS, and the nonlinear FEM results meet well with the test results. With changing the parameters of models such as Number of self tapping screw, the thickness of light steel plate, the intensity of light steel, the spacing of light steel truss and the span- height ratio of light steel truss span, a number of effective conclusions were obtained through the finite element analysis. Through the finite element calculation of composite truss beam, shear distribution coefficient of the composite upper chord are derived.Through the finite element software, analyzing the main factors which influence the effective width of composite truss beam mortar wing, and fitted out calculation formula of effective width of composite truss beam wing plate base on the data. Then the calculated results were compared with the relevant specification of steel and concrete composite beams.At last, put forward the formula of flexural bearing capacity of composite beams which considering bond-slip effect between mortar and light steel, vertical shear bearing capacity calculation formula of composite beams which considering combination of composite upper chord, deflection calculation formula of composite beam which considering oblique abdominal rod axial deformation and the bond-slip effect between mortar and light steel. And a example of finite element model is used to verify the correct of the formula given in the end.