A generalized method for estimating drifts and drift components of tall buildings under lateral loading

A generalized method for estimating the drifts of tall buildings composed of planar moment-resisting frames and coupled shear walls under lateral loading is presented. This method establishes the stiffness equations at the story levels by assuming that all the nodes in the same floor of a planar lateral-force-resisting unit have an identical lateral displacement, an identical rotation component due to the axial deformations of the columns, and an identical rotation component due to the flexural and shear deformations of the beams. By adopting this simplification, the story drifts contributed by different types of deformations, namely, the axial deformations of the columns or wall piers, the flexural and shear deformations of the beams, and the double-curvature bending and shear deformations of the columns or wall piers, can be identified. In the formulation of the stiffness matrix, the P-Delta effects were also incorporated. Through comparisons between the lateral displacements and story drifts computed using the proposed method and those computed using the structural analysis software Midas/Gen, the proposed method is proved to have high accuracy in estimating the drifts of tall building structures.