​Standing 352 feet high, McCarran’s new ATC tower is twice as tall as its predecessor. The designers recognized that this tall, slender structure needed a damping system to keep its occupants comfortable in all wind conditions. Occupant comfort always matters, but it’s especially critical for ATC professionals to be able to focus on their work without the slightest distraction. Because the tower had distinctly different frequencies on its X and Y axis, our team decided on a damping system that used a simple pendulum that could be bi-tuned.

One challenge in designing this TMD was that we needed to add 60 tons of mass in a relatively small space, while maintaining enough clearance for the pendulum to move. Only a lead-filled steel box could add sufficient mass in this small volume. Another challenge was to prevent the swinging TMD mass from overtravelling and damaging itself or the surrounding tower structure during a severe earthquake. We adopted a floor-mounted snubbing system to prevent this excessive travel.