Stiffness optimization to limit wind-induced vibrations of tall buildings

The trend towards constructing taller and slender buildings with higher strength materials has contributed to a new generation of wind sensitive structures. Modern tall buildings are in fact wind sensitive and are prone to dynamic serviceability problems. Under the influence of dynamic wind loads, tall buildings vibrate in along wind, across wind and torsional directions. Exorbitant vibrations may cause occupant discomfort or annoyance and even shatter windows. Wind-induced acceleration has become the standard for evaluation of motion perception in buildings. A practical approach to control the wind-induced vibrations in tall buildings is to limit their natural periods. An efficient computer-based technique, which involves coordinated applications of finite element analysis and design optimization processes, is developed for the optimal stiffness design of tall reinforced concrete buildings. This technique considers cross sectional sizes of structural members as design variables and minimises the structure weight subject to natural period constraints. The optimization method is fundamentally based on the Optimality Criteria approach, which has been shown to be efficient and reliable for large-scale structures. Practical building examples have illustrated that the proposed optimization method is a powerful design tool for tall building structures subject to wind-induced serviceability design constraints