Dynamic analysis method of steel-concrete composite beams based on equivalent single layer theory

Here, based on Reddy's higher-order beam theory and bond slip theory, an equivalent single-layer theoretical finite element model for dynamic analysis of steel-concrete composite beam was proposed considering effects of shear slip between concrete slab and steel beam and shear deformation of each sub-beam. Axial displacement of steel-concrete composite beam was assumed to be a third-order function along beam height so as to more accurately simulate parabolic curve change of shear stress. The advantage of this calculation model was considering in advance the shear continuity between sub-beams and the condition of no shear stress on beam's upper and lower surfaces in the constructed high-order displacement field of steel-concrete composite beam to make the equivalent single-layer displacement field function exclude the first-order derivative of beam transverse displacement, thus only C0 continuous interpolation function was needed in finite element calculation. Finally, by comparing with the numerical results in published papers, the rationality, applicable range and calculation accuracy of the proposed model were illustrated. The results showed that the equivalent single-layer theory can be used to analyze natural vibration characteristics of steel-concrete composite beam with higher calculation accuracy; the larger the ratio of height to span, the more obvious the advantage of the model. © 2021, Editorial Office of Journal of Vibration and Shock. All right reserved.