Analytical solutions for global buckling analysis of regular buildings: Inclusion of local shear deformation of walls

The critical load ratio for global buckling is a decisive parameter in structural analysis across various engineering fields. However, the complexity of coupled differential equations has restricted analytical solutions to specific cases without generalization. Aimed at broadening the applicability to various beam formulations, this paper employs the generalized sandwich-type continuous beam to propose analytical approximate solutions for the general case of arbitrary vertical loads expressible as polynomial functions. The classical sandwich beam model is a generalization of the Timoshenko beam model which includes the bending deformation of the constituents in highly contrasted composite beams, and the generalized sandwich-type continuous beam is a further generalization which also takes into account the shear deformation of the thick constituents, such as walls, a type of behavior ignored in classical literature. Equilibrium equations and boundary conditions are derived from an energy-based approach. Numerical applications and parametric analyses concern in the study of tall building stability, and more specifically of coupled shear walls. The use of the generalized sandwich beam model is particularly interesting in this context because the shear deformation of the walls is not always negligible. In all cases considered, the proposed numerical results outperform the classical model widely studied in the literature. The robust findings suggest their safe application in building structural analysis and can be readily adapted to other engineering fields by modifying the characteristic stiffnesses of the proposed model.