Effect of Local Shear Deformation and Soil Flexibility on the Global Buckling Stability of Uniform and Non-uniform Buildings

Abstract

Traditional continuous models do not capture the deformation mechanism due to local shear in coupled shear wall-based buildings, resulting in a significant underestimation of the global buckling loads. To address this limitation, the present study introduces a novel generalized sandwich-type continuous beam to derive both analytical and numerical solutions for estimating the global critical buckling load in buildings with uniform and non-uniform properties. A closed-form analytical solution is developed for uniform buildings subjected to a top-concentrated axial load, while a numerical approach – based on a modified transfer matrix method – accommodates arbitrarily distributed vertical loads and variable stiffness distributions. Soil flexibility is incorporated by modeling lateral and rotational springs at the base. The proposed numerical method maintains a constant matrix size (6 × 6), regardless of the number of discretized segments, with coefficients derived analytically. Validation against finite element models shows excellent agreement. A parametric study involving 954 cases indicates that the proposed continuous beam and its solution method limits the maximum error to –4.40%, lying on the conservative (safe) side of structural design. In contrast, the classical continuous beam shows errors up to –144.71%, raising concerns over its reliability. Furthermore, soil flexibility was found to reduce the critical buckling load by as much as 46.09%. The results underscore the robustness and practical applicability of the proposed continuous beam and its solution methods, providing a reliable framework for the structural analysis and design of buildings with coupled shear walls.