Deformation of steel-concrete composite beams under constant amplitude fatigue loading

With degeneration of material properties and accumulation of damage under fatigue loading, deformation of steel-concrete composite beams increases. Therefore, it´s necessary to evaluate the additional deformation caused by fatigue loads. Based on research results world widely, constitutive relations of materials such as concrete and steel were chosen properly, and simplified calculation formulas of shear stiffness of studs subjected to fatigue loads were deduced. According to the differential equation of slip at the interface between the steel girders and concrete slabs, a method was presented to calculate the deformation of composite beams under constant amplitude fatigue loads. The comparison between calculated values and test results showed that the proposed method was feasible and it could provide references for the deformation calculation of composite beams over the fatigue life.