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.
Evaluation of buckling load and dynamic performance of steel shear wall retrofitted with strips made of shape memory alloy
One of the most imperfections of the steel shear wall is out of plane displacements that cause severe damage in both structural and non-structural elements. In this paper, the effects of shape-memory alloys on steel shear walls are investigated. First, a numerical analysis using the finite element method in ABAQUS software has been carried out according to an experimental test. The results of the numerical analysis have been verified with experimental results. Next, shape-memory alloy fibers have been added vertically and horizontally to various parts of the steel shear wall. The results show that retrofitting with the shape-memory alloy reduces the out-of-plane displacement of the steel shear wall under both cyclic and seismic loadings. Besides, the buckling load in the steel shear wall increases when it is retrofitted with the shape-memory alloy. Also, the total out-of-plane movement (accumulated absolute displacements) of the steel shear wall and non-structural damage are controlled by the characteristic of a shape-memory alloy material called “super-elastic”.