Mechanical Performance Study Of Steel And Concrete Composite Beams With Elastic Shear Connection

A large amount of project practice proved that steel-concrete composite beams have the advantages of both steel structure and concrete structure, It is a significant technical and economic benefits and social benefits of the new structure system, and the broad prospect of application in the future. It is one of the important developing direction of civil structural system in the 21st century. Because the steel-concretes composite beams interface slip effect that lead to reduction of stiffness of composite beams and increase its deflection,and its will become more and more researcher concerns.Firstly, in order to reduce the composite beams interface slip in this thesis, a shear connectors distribution way is proposed that is to use a step uniformly distributed without any increased amount of connectors. Therefore choose reasonable mechanical model, a slip differential equation of composite beams is established according to the interfacial geometric and constitutive and balance relationship of composite beams. And the slip analytical solutions for step uniformly distributed shear connector are solved. Through the comparative analysis, Calculation results show that this method is effective to reduce the composite beams interface slip. Thus can reach to improve the tiffness, bearing capacity and durability.Secondly, based on the viewpoint of the structure systems energy, According to minimal potential energy principle, deduces out the axis force variation model of composite beams. Thus axis force differential equation of composite beams is established.and the axis force analytical solutions are solved. Then the deflection differential equation is established by the relationship between the deflection and curvature of composite beam. Composite beam deflection formula of elastic shear connection be solved by the gradual integration methods. and the deflection analytical solutions of composite beams under a concentrated load at the mid-span and symmetrical concentrated loads and uniform loads are solved. Compared with Reduced Stiffness Method, Calculation results show that Reduced Stiffness Method exist applicable scope and limit condition.Finally, most numerical simulation computations by using Finite Element Software ANSYS. Includingthe interface slip and axis force and deflection of composite beams under four typical loads. And compared numerical analytic results with the theoretical calculation. Calculation results show that theoretical calculation and finite element numerical simulation results in good agreement with.