DeSimone Consulting Engineers, New York City
Development in dense urban centers is continuing at a blistering pace. Mature cities such as Miami and New York, hampered by a lack of available building lots and arcane zoning requirements are forcing developers to build taller and more slender buildings. Novel uses of air rights and overbuild methodologies are also creating uniquely-shaped, inverted towers as a result of the desire to maximize the amount of premium “for sale” product. Supplemental damping has become more commonplace than ever for tall and supertall buildings. Often, the introduction of supplemental damping is an afterthought, brought about by the result of a wind tunnel study that indicates performance at levels below what is acceptable.
Common assumptions regarding factors affecting building stiffness, inherent damping and mass are challenged as a result of long-term building performance monitoring. In-situ measurements of tall building performance have allowed practitioners to move beyond prescriptive stiffness and damping assumptions, allowing us to not only optimize material use, but also to better predict building performance throughout a wide range of load levels. This presentation offers a summary of predicted and measured behaviors and identifies methodologies for optimize building performance and developing supplemental damping requirements for future projects. Several case studies are also presented, highlighting the evolving approach to analysis as a result of the information gleaned from the data gathered from the presenters’ portfolio of tall buildings.