Posted on : Wednesday 29th July 2020 02:36 PM
The supertall skyscraper Taipei 101 also called Taipei World Financial Center located at Taipei, Taiwan once held the record for the world’s tallest building from 2004 until 2010. This 101-story tower with a five-story deep basement is designed by architect C.Y. Lee and C.P. Wang. Other than the 509.2 m height, this building was popular for its elevator speed and the ability to withstand typhoon winds and earthquakes using the tuned mass damper(TMD). In Taipei 101 skyscraper, the TMD also called harmonic absorber or seismic damper is mounted to the structure for reducing the impact of vibrations and to protect the structure from hazards. This article focusses on important hydraulic applications in this tall skyscraper.
If considering some facts of Tuned Mass Damper(TMD) in Taipei 101, it is the world’s largest and heaviest TMD with a weight of 660 metric tons. This TMD has a pendulum-like structure and it includes a gigantic yellow sphere that is suspended on cables between the floors 87 and 91. The TMD oscillates in the opposite direction of vibration to provide stability to the structure and occupant. The TMD in Taipei 101 can protect the structure from wind up to 135mph and it can move 5 ft in any direction.
The Tuned Mass Damper contains a mass block, bumper system, cable, and hydraulic viscous damper. The 18-foot diameter huge mass block is constructed by welding 5 inch thick plates together and steel cables are used to hold the sphere structure. The eight hydraulic cylinders(each side contain two) will support the bottom of the mass block just like its legs. The hydraulic cylinder is connected using a universal joint between the mobile plate and fixed base. The cable and hydraulic cylinders together will allow the mass block to move three dimensional.
What is the hydraulic viscous damper in TMD? It is a hydraulic device that works based on the principle of the dissipation of energy and it contains components like a hydraulic cylinder containing two chambers, piston, piston rod, lining, medium, pinhead, etc… The movement of the piston rod causes fluid to flow from one chamber to another through the orifice and results in energy dissipation. This damping device operates when any movement on the structure is induced due to external stimulation.
The extension of the hydraulic cylinder will move the mass block and it acts as an opposite force for dampening the effect of wind and earthquakes. The dampening force created by a hydraulic viscous damper will depend on the impact on the building structure. For a sway that is induced by small wind, the dampening force created will be also negligible, where it will be difficult to identify that movement. But, for heavier intensity circumstances like earthquakes and typhoon wind, a drastic rise in resistance can be found and this will lead to a “lockdown” effect that resists the mass block from further movement and protects the system
Tuned Mass Dampers(TMD) that reduce undesirable oscillations, uses the minimum number of moving parts and almost no maintenance will be required for it in the future after installation. Proper plating and painting are required on all materials to prevent corrosion and the piston rod is always constructed using fully heat-treated solid stainless steel. The common hydraulic fluid used for TMD is cosmetically and chemically inert Silicone oil, having features like non-flammability, non-combustibility, high flashpoint(over 600°F), thermal stability, etc...