Soaring 1,667 feet over Taiwan, Taipei 101 was once the world's tallest building. Standing in a region plagued by powerful typhoons and frequent seismic activity, the mega-structure faced a massive engineering challenge: how to prevent extreme winds and earth tremors from causing catastrophic structural swaying. The solution was as eccentric as it was brilliant—a 660-metric-ton tuned mass damper (TMD).
Suspended in the heart of the tower from the 92nd to the 87th floor, this giant pendulum consists of 41 circular steel plates welded together to form a sphere measuring 18 feet in diameter. When high winds or earthquakes push the tower in one direction, the pendulum sways in the opposite direction, acting as a dynamic counterweight. This opposing motion absorbs up to 40 percent of the building's lateral sway, drastically reducing dynamic inertia and preventing structural damage while keeping occupants from getting motion sickness.
The damper is supported by eight massive steel cables suspended from the floor above, paired with hydraulic viscous dampers below that dissipate the pendulum's energy as heat. Uniquely, Taipei 101 left its TMD exposed to the public, turning a critical engineering feat into a major tourist attraction, complete with its own cute mascot characters called Damper Babies. During Typhoon Soudelor in 2015, the sphere moved a record 39 inches, proving its vitality.