Web buckling analysis of steel-concrete composite beams considering flange restraints

A mechanical model was established to study the buckling of the web of steel-concrete composite beams under flange restraint. Based on the Rayleigh-Ritz variational methodology and elastic buckling theory, a theoretical buckling calculation model for steel-concrete composite beams with webs restrained by flanges was proposed. Through a parameter analysis, the variation in the web buckling coefficient with the rotational restraint coefficient of steel-concrete composite beams under different web aspect ratios and stress gradients was studied. The calculation accuracy of the proposed theoretical model was verified by comparing the calculation results under different parameters with those of a traditional model. Finally, considering the different distributions of the shear studs, the theoretical model proposed in this study was verified using the finite element method. The following results were obtained: the deviation between the theoretical model and the traditional model was less than 3 %, when the spacing of shear studs increased from 100 to 1000 mm, the critical buckling stress calculated by finite element method decreased from 121.90 to 113.29 MPa, with a deviation of less than 6 % from the theoretical model in this paper, both the theoretical model and the finite element calculation show that when the elastic restraint coefficient was greater than 20, the buckling coefficient region was constant.