This paper suggests that more efficient and high performance tall buildings can be designed if engineers consider the dynamic performance of a building as a separate and unrelated issue to the strength needs of a tower. When considering the dynamic performance of a tower, it is often more effective to add damping to a building to improve the vibration performance rather than to add stiffness, mass or strength. Although engineers have been adding Tuned Mass Dampers (TMDs) to tall buildings for years, the typical approach has been to add material and or damping to a building after the initial wind tunnel test rather than to optimize the structure to meet the strength requirements and then resolve the acceleration issues. The authors suggest that in the future, viscous dampers in tall buildings will be much more common as they allow additional damping to be provided without increasing the weight of a building, and allow the structure to be optimized for strength and for accelerations separately. An example of this approach is shown for a 40-story tower under construction in New York City. This all steel 860,000 sq. ft. tower has a steelwork weight of 22psf and incorporates seven viscous dampers to meet the acceleration requirements. A conventional solution would have involved another approximately 1,000 tons of steel, or required the addition of a damper plus additional steelwork.
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