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, the relative slippage exists between 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 about 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 the rigidity increment of the shear connectors. The stress of the steel girder and the deflection of the composite girder decrease with the rigidity increment of the shear connectors.
A Shear Lag Analysis for Composite Box Girders with Deformable Connectors
A method is proposed for shear lag analysis which can be applied to steel-concrete composite box girders. The proposed method uses harmonic analysis and allows the determination of shear lag effects from simple calculations so that the method is regarded as a design aid. The character of the method can illustrate the influence of certain key parameters upon the extent of the shear lag effect.
Nonuniform Bending‐Stress Distribution (Shear Lag)
Nonuniform normal longitudinal stress distribution in a trapezoidal box beam with lateral cantilever is discussed. The problem is solved by the variational method assuming as unknown the displacement of the beam axis and three functions which describe the warping of the horizontal flanges; the unknowns are reduced in case of vertical walls. The state of stress of stress in each structural element is analyzed and an example is given to illustrate the results.