Mechanical properties analysis of steel– concrete–steel composite beam:

The interface slip will appear between the steel plates and concrete while the steel-concrete-steel composite beam under loading. It may influence the mechanical properties of the composite beam. In this paper, through theoretical analysis of the steel-concrete-steel composite beam, differential equation of interface slip is established at first. By simulating the real boundary, the formulas of interface slip are calculated under uniform and arbitrary concentrated load. Then, the axial force, the sectional curvature, and deformation of composite beams are obtained. In order to validate the reliability of the theoretical analysis, the deformation of 18 samples is calculated by using the deformation formulas of steel-concrete-steel composite beam. The results are in good agreement with the experimental consequences. Through an example, the mechanical properties of composite beams (axial force, sectional curvature, and deformation) are analyzed under interfacial slip. With the decreasing of interfacial slip, axial force of upper plate increases, and sectional curvature and deflection decrease. For lower steel plate, the interfacial slip has smaller effect.