The Shanghai Tower’s Eddy Current Damper uses a series of copper plates and magnets (pictured above) to help reduce building movement. Image © Noah Sheldon
With only the final scaffolding remaining on the Shanghai Tower’s crown and the upper most beam in place, we can now fully visualize the building’s complete silhouette. As visually stunning as the curved tower is, the special features hiding within the silhouette, especially in the tower’s crown, are just as exciting. The tops of most buildings only feature observation zones for tourists, while masking the less interesting but mandatory mechanical elements with opaque glazing. The Shanghai Tower’s crown will of course encourage visitors to enjoy the unparalleled views of Shanghai, but it will also direct gazes towards the inner workings of the building itself and provide glimpses of wind turbines, a rain water collection system and two types of dampening systems: a Tuned Mass Damper (TMD) with Eddy current damping applied. These last two are both near completion.
As you may imagine, buildings that are “super tall,” such as Taipei 101 and the Burj Kalifa, are regularly buffeted by natural phenomena such as wind of varying strength and tremors that can often times cause the buildings to move or sway. Mitigating sway in a superstructure is important not just for the comfort of the tenants inside the building; it is also reduces structural fatigue over time.
The Shanghai Tower’s TMD will sit within this space. Image © Noah Sheldon
The Shanghai Tower TMD is essentially a large weight designed to counteract sway. The Shanghai Tower’s TMD structure is, to say the least, large. It is five floors in height (from the 125th floor to the 130th floor) and carries a 1,000 metric ton weight. Needless to say, a weight this large cannot move willy-nilly in the building’s crown as it counteracts the sway of the building. The movement of the TMD is suppressed to a manageable amount by Eddy currents and magnetic fields.
An Eddy Current Damper, the second dampening system in the Tower, is a series of copper plates and magnets designed to work together with currents to help control building movement or sway. The Eddy current damper sits below the TMD at the 125th floor, and is 400 meters in height and roughly 10 x 10 meters square. When both features are complete the devices will reduce building displacement by 20 percent and acceleration by 40 percent.
Workers near the building’s crown. Image © Noah Sheldon
Mr. Qian Feng (钱峰), Project Director of Shanghai Research Institute of Materials and TMD engineer says the five story TMD frame is already built and the twelve cables that support the main weight are in place. The TMD weight itself consists of 300 steel plates of different sizes. The tower crane will lift each piece that serves as dead weight from ground level to the 125th floor.
Designed to be a fully interactive experience, tourists visiting the observation areas in the Shanghai Tower’s crown will be able to view a sculpture installation hanging directly above the TMD as part of the Tower’s unique visual experience 600 meters in the sky. The TMD is expected to be in place this week, and there is so much more to go before completion! Stay tuned for more updates in the coming weeks.
 |
Robert Price is a senior associate in Gensler's Shanghai office. He has more than 25 years of experience in corporate interiors, retail and commercial architecture. Contact him at robert_price@gensler.com. |