LAUSR

Abstract In this study, the optimum locations of outriggers minimizing the top drift of tall buildings are identified using a gradient-based nonlinear programming approach. Since the proposed optimization method uses finite element analysis to evaluate the objective function for arbitrarily configured buildings, the discontinuity due to design variables (such as outrigger locations) is overcome by piecewise linear and quadratic interpolation functions. A series of optimum designs for three analysis models with different vertical profiles were performed to investigate the relation between outrigger stiffness and optimum location by changing the cross-sectional area of outriggers. As outrigger cross-sectional area increases, the optimum outrigger location moves down in the structure. The design result demonstrates that correlation between outrigger stiffness in a practical range and its optimum location is negligible; thus, for design purposes, variables related to outrigger optimum location and its stiffness can be dealt with separately.