An integrated design technique of advanced linear-mode-shape method and serviceability drift optimization for tall buildings with lateral–torsional modes

Abstract

The advance to ever-taller and complex-shaped buildings requires a more accurate determination of dynamic wind loads for structural design purposes through wind tunnel tests. The three-dimensional (3D) mode shapes found in complex tall buildings complicate the use of the high frequency base balance (HFBB) technique for predicting wind-induced loads and effects. The linear-mode-shape (LMS) method was recently proposed to address some of the complications in the calculation of the generalised wind forces, which serve as the input to modal analysis for predicting wind-induced dynamic responses of tall buildings. The advanced linear-mode-shape (ALMS) method, a modification of the LMS method, is developed in this paper by introducing torsional mode shape corrections to take into account the partial correlation of torques over building height. The ALMS method is then incorporated into the accurate complete quadratic combination (ACQC) method to form a comprehensive framework to predict the equivalent static wind loads (ESWLs) for structural design of tall buildings. Then, an automated stiffness optimization technique integrated with the ESWL framework is developed for serviceability drift design of complex tall buildings with 3D mode shapes. A 60-storey building with an asymmetric structural system tested in a wind tunnel is used as an illustrative example. Encouraging results demonstrate that the integrated design optimization technique is able to produce a more economical element stiffness distribution of the example building, satisfying multiple serviceability wind drift design criteria while allowing for an accurate update and determination of the equivalent static wind loads under multiple wind angle conditions.