Most skyscrapers can quickly move several feet in either direction, like a swaying tree, without damaging their structural integrity. However, high wind and vibrations can cause damage and unnecessary shifts in the building’s structure. The main problem with this movement or acceleration is how it affects the people inside. If the building moves a substantial horizontal distance, the occupants will feel it experiencing a form of motion sickness. Adding a Tuned Mass Damper (TMD) can help alleviate this problem, prevent damage, increase occupant motion comfort, and improve elevator performance, thus achieving optimal structural performance. For this reason, developers of skyscrapers are installing TMDs at the top of towers to counteract building motion. Although most developers will not promote this as a feature, it is a cutting-edge technology for high living comfort.
Metropolitan Walters involvement with TMDs started with Lend Lease and Motioneering (a division of RWDI), a wind engineering and environmental engineering consulting firm that designs dampers as a machine-type system.
“We were approached in 1998 by the contractor Lend Lease and Motioneering to design assist the team in developing a TMD on the Trump World Tower. With our extensive knowledge in structural steel connection and the expertise of the principal of Motioneering at that time – Brian Bruckelman, we could provide the team with a cost-effective solution, a Passive Tuned Mass Damper. This Passive TMD solution utilized structural steel connections common to our industry in lieu of machined fitted bolts used in manufacturing, reducing, and eliminating unnecessary machined surfaces. As a result, we were able to meet the budget,” said David Prescrita, CEO of Metropolitan Walters. “Now we needed to build it. Well, I knew we could fabricate all the steel components and integrate lifting and assembly practices common to our field. But some machining still existed, so we reached out to A&H Custom Machine LTD., a mass damper manufacturer, to perform the machining and the rest is history.”
“Since 1998, we have worked together as THE TMD TEAM, improving the design, buildability, and ease of installation of every TMD. Our relationship is built on integrity and trust,” said Gerard A Woudenberg, Business Development at A&H. “Having the three key stakeholders on board (Design, fabrication and installation), together with our portfolio of successful projects, gives the client peace of mind on something (TMDS) they know very little about.”
Passive dampers reduce the wind-induced building. The ratio of the stiffness of supporting members to the frame stiffness is critical in the effective use of passive dampers. Therefore, the optimal damper placement depends strongly on building structure models. The mass design hangs as a pendulum. As the building moves, it causes the mass to move. The mass movement is dampened by Viscous Dampening Devices (VDD). This mechanism reduces the sway motion to an acceptable level whenever high winds hit.
For over 20 years, Walters has worked with A&H Custom Machine in Burlington, Ontario and Motioneering in Guelph, Ontario, combined with Metropolitan Walters field services to be on the leading edge of technology and TMD installation. Recently, A&H supplied the largest TMD built to date for Central Park Tower located at 217 West 57 in New York City. Central Park Tower is currently the tallest residential building in the world, standing at 472.44 meters (1,550 feet) above ground. This building was designed to include several cantilevers on the upper floors increasing the square footage of the building along with the weight and sway. For this reason, it required a tuned mass damper larger than had ever been built.
Working with the same principles as needed for a smaller opposed pendulum-style tuned mass damper, A&H made this large TMD at their facility in southern Ontario. Also, machined parts were made for the trial assembly. The key to this TMD’s success was the coordination and cooperation between all disciplines, including design, fabrication, installation, tuning and conditioning. As a result, even though the TMD remains the largest TMD built to date, it has the same features as a smaller, opposed pendulum-style TMD.
Video credit A&H – Tuned Mass Damper in operation on top of Central Park Tower in New York City
Together with RWDI and A&H, Metropolitan Walters has installed passive mass damping systems worldwide. In addition, we can assist with specific requirements of buildings, bridges, towers, or any other project that requires a tuned mass damper.
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About Walters Group
Walters Group is a steel construction company that designs, fabricates, and constructs commercial and industrial projects throughout North America. Through an integrated network of companies, we provide products and services that complement the core business of structural steel. From Architecturally Exposed Structural Steel (AESS) to high-end architecturally fabricated structures to the latest in lightweight flooring technology, we can bring innovative ideas and solutions to our clients. waltersgroupinc.com
About A+H
A+H Tuned Mass Dampers is a world leader in the supply and fabrication of TMD’s. In collaboration with the key stakeholders and together with our strategic partners, we provide world class solutions. Tuned Mass Dampers are installed in structures that require supplemental dampening worldwide. ahcustom.com
About RWDI
RWDI is a globally renowned environmental engineering firm tackling complex challenges in the built environment. We drive success on ambitious building, industry, and infrastructure projects – enhancing their performance and efficiency, and assessing and mitigating their environmental impacts. rwdi.com
