Stiffness Optimization for Wind-Induced Dynamic Serviceability Design of Tall Buildings

Contemporary tall buildings with increasing height and slenderness are highly sensitive to the actions of wind. The structural design of modern tall buildings is generally governed by the need to provide adequate strength and stiffness against dynamic movement induced by strong wind. In addition to the strength-based safety design considerations, the major design effort of a tall building is related to the assessment of the wind-induced serviceability design requirements in terms of lateral drift and motion perception criteria. With tall buildings of today continuing to increase in height, the mitigation of wind-induced vibrations in tall buildings becomes a more critical challenge in the design synthesis process. This paper presents an integrated dynamic analysis and computer-based design optimization method for minimizing the structural cost of tall buildings subject to wind-induced serviceability acceleration design criteria. Once the optimal dynamic serviceability design problem is explicitly formulated, a rigorously derived optimality criteria method is developed for seeking the optimal distribution of element stiffness for a tall building system, satisfying the peak acceleration design constraints. Two full-scale 60-story building examples of mixed steel and concrete construction, with and without complex three-dimensional (3D) mode shapes, are used to illustrate the effectiveness and practical application of the optimal design technique. The results showed that the computer-based optimal design technique provides a powerful tool for wind-induced dynamic serviceability design of tall general buildings with complex 3D mode shapes.