Analysis of Stress and Deflection about Steel-Concrete Composite Girders Considering Slippage and Shrink & Creep Under Bending

Steel-concrete composite beams are composed of concrete slabs and steel girders by shear connectors. Due to the limited rigidity of shear connector, and the shrink & creep property of concrete, relative slippage exists between the concrete slab and steel girder under bending, and it is difficult to analyze the effect of those factors by the ordinary beam theory, the finite element method(FEM) and so on. A differential equation of equilibrium is constituted corresponding to the compatibility of deformation and the equilibrium of forces of steel-concrete composite beams under particular assumed condition. Finite difference method (FDM) and variation principle are used to solve the differential equation. An example of steel-concrete composite T girder is given to analyze the effect of slippage and concrete shrink & creep on its stress and deflection. The concrete slab stress increases with increased rigidity in the shear connectors. The stress of the steel girder and the deflection of the composite girder decrease with increment in the rigidity of the shear connectors.