A novel generalized sandwich-type replacement beam for static analysis of tall buildings: Inclusion of local shear deformation of walls

As the length of the shear walls increases, local shear deformation leads to increased error when using classical continuum models for static structural analysis of tall buildings. In this paper, a novel continuous beam of the generalized sandwich type is proposed for the structural analysis of tall buildings that have shear walls of significant length as lateral bracing systems. The proposed continuous beam includes in its formulation an additional kinematic field of rotation due to the local shear deformation of the walls and results from the series coupling of a classic sandwich beam and a shear beam. The equilibrium equations, the constitutive laws, and the boundary conditions of the continuous model are obtained with a variational approach using the Hamilton principle on the relevant Lagrange function. A system of three coupled differential equations leading to sixth-order differential equation and six boundary conditions are obtained. Two closed-form analytical methods are proposed for uniform-height tall buildings. For the case of buildings with variable properties along their height, a numerical method of the modified transfer matrix type is proposed, which is directly derived from the analytical method and avoids the need to calculate the inverse of the classical zero transfer matrix method. The numerical results show the validation of the continuous model and the proposed solution methods. In addition, a parametric analysis of 352 buildings was performed to demonstrate the superiority of the continuous model and the proposed solution methods.

Automated summary

In this paper, a novel continuous beam method is proposed for the structural analysis of tall buildings with long shear walls. The proposed method considers the rotation kinematic field due to the shear deformation of the walls and is derived from the coupling of a classic sandwich beam and a shear beam. The equilibrium equations, constitutive laws, and boundary conditions of the continuous model are obtained using a variational approach. Closed-form analytical methods are proposed for uniform-height buildings and a numerical method is proposed for buildings with variable properties along their height.