Over fifty years ago, supplemental damping systems were introduced to mitigate vibrations in tall, slender structures. Since then, their use has been extended to existing tall buildings and new construction. Like a shock absorber for your car, a supplemental damping system has the same function for a tall building (normally 50 stories or taller) – it mitigates harmonic motions, particularly in the wind.
Without sufficient damping, a building can vibrate in both directions and in certain cases can create a circular movement, causing discomfort for individuals in the building. The acceleration and feeling that the building is going in one direction, then slowing down and going in another direction, can cause physical and psychological discomfort for those who experience it. Some tall buildings require supplemental damping to achieve the desired occupant comfort.
A vast amount of literature exists on the topic, mostly composed of papers published in research journals that examine detailed issues on the design, function, and effects of tall building dampers. Because of the fragmentation of sources, knowledge in the field is inaccessible by people who are interested in the topic and remains restricted to specialized experts—until now.
I had the pleasure of being part of The Building Damping Technologies Working Group, formed to study the Council on Tall Buildings and Urban Habitat (CTBUH) research project, “A Study on the Damping Technologies Available for Tall Buildings: Comfort and Safety,” funded by Bouygues Construction.
What started as a technical guide for the design of tall buildings has grown into a voluminous treatment of the subject with practical explanations. I reviewed the chapters in the book on practical applications, and as part of my role I gave authors feedback on whether the information could be applied by practicing structural engineers. Most importantly, I wanted to make sure engineers could open the book, read the content thoroughly, then apply the knowledge to buildings.
The book took about two years to complete, culminating with a book launch in Dubai in October 2018. Not only is the city of Dubai a special place, it is also home to the tallest building in the world, Burj Khalifa. (It does not have a damper in it). The Burj Khalifa, which is the first-of-its kind project in the world, is strategically positioned so it is not in a high earthquake or high wind zone, and its structural configuration is such that it does not require supplemental damping.
CTBUH facilitates the exchange of the latest knowledge available on tall buildings around the world through publications, research, events, working groups, web resources, and its extensive network of international representatives. The organization has gathering the state-of-the-art scientific, technical and practical information on supplemental damping systems into this single book. My hope is that practicing structural engineers can use the practical information and apply it directly to their projects.
By Kirk Harman