The Taipei 101 Tower, Taiwan: The Tallest Building on Earth, made using Steel

H. K. D. H. Bhadeshia

Until 2010, the Taipei 101 Tower of Taiwan was the tallest building on Earth. Its height above ground is 509.2 m. This includes the 60 m spire; the building also holds the record for the highest roof (440 m). Since January 2010, the Taipei Tower ceded its record height to the Burj Khalifa in Dubai.

The Taipei 101 Tower contains the world's fastest and most comfortable elevators. The building is thrilling to look at, an impressive tribute to steel, glass and incredibly clever engineering. And yet the design clearly reflects the local Chinese culture; for example, there are eight canted sections, eight being the lucky number in Chinese. Each section is embellished with a traditional Chinese symbol of fulfillment, the symbols being large enough to be visible from the ground.

The region where it is built straddles the Pacific Ring of Fire, an arc of fault lines that erupt in earthquakes every decade or so. There are also many typhoons in this region. There are therefore massive support columns and braces in place. Pairs of 2.46 by 3.1 m supercolumns on each face of the building work, together with 16 columns in the core form the vertical support structure.

The massive supporting pillars are made of boxes of 80 mm thick steel-plate, filled with concrete for stiffness. However, only steel is used above the 62nd floor. There are 16 of these giant columns to support the gravity-load. There are many lateral braces and moment-resisting frames around the building perimeter.

Wrapped around the supercolumns is a web of a ductile steel framework designed to bend during an earthquake. The frames support the outward slope of the building, making possible the repeating inverted pyramid shape.

There is a dedicated mechanical floor every eight floors, with massive floor-high steel outrigger trusses. These connect the columns in the core to the supercolumns on the perimeter, effectively widening the building to help it resist overturning.

Given the strenuous geographical circumstances, the engineering and materials technologies involved in the construction of this supertower are remarkable. The tower is made from pliant steel, which is strong and yet has a low yield to ultimate tensile stress ratio so as to be able to accommodate plastic strain in the event of natural disasters. The steel is at the same time, weldable, so the concentration of alloying elements permitted is rather low. The steel is microalloyed, thermomechanically processed and accelerated cooled to produce a fine microstructure without the excessive use of alloying elements which can compromise weldability. Five different kinds of steel plates were used, with yield strengths in the range 412-510 MPa and tensile strengths in the range 570-720 MPa. In all cases, the carbon equivalent (P_cm was less than 0.29. The plates were produced using the TMCP process. Specially constructed steel processing plant are needed to manufacture such alloys.

In addition, the tower is supported by 380 concrete-filled steel piles, sunk into the soil to a depth of 80 m.

Vibrations are damped by suspending a massive steel ball weighing 606 tonnes; steel is a wonderfully dense material; the volume of an aluminium ball would be some three times as large, which is intolerable for such an elegant design. The ball is suspended from the 92nd floor to reduce lateral vibrations. The ball is in fact made from a stack of steel plates of varying dimensions. It is connected to pistons which drive oil through small holes, thus damping vibrations. The photographs below show the ball during the construction stage of the building.

In its final form both the ball and the eight high-strength steel cables which cradle it, are painted gold. This is the largest wind-damper on Earth.

While the large, tuned steel damper helps protect the main structure, the tower's 60 m spire relies on two smaller dampers to relieve the nearly constant wind buffeting. Without this damping, the vibration would lead to metal fatigue and failure within decades. Because of space constraints and the need for a large mass, the 4 tonne dampers are placed on rails that fit around the interior columns of the spire. The energy absorbed by the dampers in the spire is dissipated into a system of springs beneath the mass (China Times, 25 October 2003).

Two of the elevators in the building ascend at 17 m s^-1 and yet present a comfortable ride; these are the fastest lifts in the world (34% faster than the previous record holder, the Yokohama Landmark Tower in Japan. They contain pressure control systems which adjust the atmosphere inside the elevator to prevent ear-popping. There are also active control systems which eliminate vibrations. The elevator cars are aerodynamically engineered to reduce the noise resulting from air flow as the lifts travel at high speed inside their narrow shafts. Alain Robert, the French Spiderman took four hours to climb the tower.

The photographs below were made possible by Professor C. H. Young who kindly arranged for Chun Chen Wei (his former student, now a construction engineer on the project) to guide us through the formative stages of the construction project.

Note: China has cancelled plans to build a slightly taller tower in Shanghai.

The Taipei 101 Tower.	The Taipei 101 Tower, the tallest building in the world.	Outside the Taipei 101 Tower, Professor Young (National Taiwan University of Science and Technology) and Professor Chun Wei Chen (National Taiwan University)
		Professor Young (right) arranged for a private visit to the 101 building. The building will officially open in January 2005
Sculpture outside the 101 building	The shopping complex on the left is attached to the Taipei 101 Tower by a flexible joint illustrated here	The massive supporting pillars are made of boxes of 80 mm thick steel-plate, filled with concrete for stiffness. However, only steel is used above the 62nd floor. There are 16 of these giant columns to support the gravity-load. There are many lateral braces and moment-resisting frames around the building perimeter.
Prepared for the private visit to study the engineering that has led to this tremendous success. Young, Chun Chen Wei, Harry, Yang and Chen. Wei is Professor Young's former student, now involved in the construction of the Taipei 101 Tower and our guide. All except Wei are alumni of Cambridge University.	Professor L. C. Hsiung of the Chung Cheng Institute of Technology	The massive supporting pillars are made of steel, filled with concrete. However, only steel is used above the 62nd floor.
The steel ball weighing 606 tonnes, used to damp vibrations.	The steel cables which cradle and suspend the ball.	The steel cables which cradle and suspend the ball.

		The 101th floor
Fire-proofing on steel beams.	The view from the roof of the Tower.	The view from the roof of the Tower.

	On the roof of the Taipei 101 Tower. The Tower will formally open in January, after which, visitors will only have access up to level 91.	Chun Chen Wei on the highest roof of the Taipei 101 Tower.
	The view from the top.	The lower part of the 60 m spire on the roof.

	The observation deck on floor 91 (there is another one on floor 89 with a the highest restaurant in the world - the general public will not be able to access higher levels.	These massive trusses located at eight levels support the building in the event of an earthquake. The building is in principle able to resist a Richter scale 10 earthquake.
The part of the building above the 91st floor. When the building opens, the public will be limited to floors below the 91st, where there is a viewing gallery.	Grain structure of galvanised iron used to protect the trusses. each grain is about 1 cm in size	Grain structure of galvanised iron used to protect the trusses. Each grain is about 1 cm in size.
The base of the truss, with the galvanised steel.	On the 91st floor.
The stairwell.	The sphere is made from thick steel slabs which are stacked and welded together.	The lower half of the spherical pendulum.
The weld between each constitutent slab of steel in the spherical pendulum.	Professor Jen Ren Yang in front of the spherical pendulum.	Professor Chun Wei Chen in front of the spherical pendulum.
Professor L. C. Hsiung in front of the spherical pendulum.	Chun Chen Wei and Professor Chin-Huai Young in front of the spherical pendulum.
Some of the elevators in the building are capable of climbing at 60 km h^-1, with special damping to give a comfortable feel during acceleration. These are the fastest elevators in the world.		Construction in progress.
A huge book shop in the shopping mall which connects to the Taipei 101 Tower.	The elegant steel structure supporting the roof in the shopping mall.	The elegant steel structure supporting the roof in the shopping mall.
The flat concrete slabs are less dense than water. They are made from special concrete (designed by Professor Young of the National Taiwan University of Science and Technology). They are made by mixing cement and porous clay (obtained by dredging silt at the bottom of a dam).	The fact that the concerete slabs have a density of only 0.9 that of water means that it is possible to have a huge reception hall in the shopping mall.
	Inside the 'Page One' bookshop. Notice the Audrey Hepburn record on sale.	Inside the 'Page One' bookshop.
The Taipei 101 Tower at night. Photograph taken from a moving car.

The above pictures were taken by Harry Bhadeshia during 2004. The images shown below are due to Dr Thomas Sourmail, who took them in 2003.

The Taipei 101 Tower, tallest tower in the world.	The Taipei 101 Tower, tallest tower in the world.
The Taipei 101 Tower, tallest tower in the world.
The Taipei 101 Tower, tallest tower in the world.		The Taipei 101 Tower, tallest tower in the world.

The Tower, revisited in November 2005

T101, the highest building on earth, revisited at night.

T101, the highest building on earth, revisited at night (Yang and Harry)

More pictures of Taiwan

More structural details, September 2023

Chrysalis art with used elevator cables from Taipei 101. The art is located in the viewing area high up in T101	The steel cable, which is pearlitic, and very strong in the cold-drawn condition, is arranged in a truly elegant shape.
Close-up of the steel cable used to shape the Chrysalis	A view from the top observation deck
Note the twisted building at the centre of the image
Helipad at the top of the twisted building	Another interesting, tall, steel+glass building
The interesting structure at the top probably hides services	The tuned damper
Harry and the damper	Jer-Ren Yang and the damper
Beautiful pearlitic-steel cables	Shows the suspension of the 606 tonne steel ball
The ball represents the largest object ever made using additive manufacturing, where thick steel plates of different diameters are welded togethher to generate the shape
Showing the dampers connected to the steel ball	We counted 12 damping devices


Showing how the steel cables are secured	The ball is supported underneath by a sort of a cradle



How the damper works	A nice schematic
Other tall buildings have different damper designs	Other tall buildings have different damper designs

The Yokohama Tower which has a computer-controlled active damper	Sunset in Taipei