Canton Tower

Canton Tower, formerly Guangzhou TV Astronomical and Sightseeing Tower,is an observation tower in the Haizhu District of Guangzhou, historically known as Canton or Kwangchow, Guangdong, China.The tower was topped out in 2009 and it became operational on 29 September 2010 for the 2010 Asian Games.The tower briefly held the title of tallest tower in the World, replacing the CN Tower, before being surpassed by the Tokyo Skytree in 2011.It is the tallest structure in China and the fourth-tallest freestanding structure in the world. It is named after the traditional European name of the city.

History
The tower is designed by the Dutch architects Mark Hemel and Barbara Kuit of Information Based Architecture together with Arup, the international design, engineering and business consulting firm headquartered in London, United Kingdom. 2004, Information Based Architecture and Arup won the international competition, in which many internationally large architectural offices participated. The same year the IBA - Arup team in Amsterdam, developed the tower's concept design.

In later stages, IBA cooperated mainly with the local Chinese office of Arup and a Local Design Institute. The tower, although not fully completed, opened to the public on 1 October 2010 in time for the 16th Asian Games, hosted by Guangzhou in November 2010.The rooftop observatory finally received its official opening in December 2011.

Structural Concept
The tower was designed by Information Based Architecture and Arup. The Arup team led by structural engineer Prof. Dr. Joop Paul introduced near mass customisation to the joint design, in combination with parametric design methods, and applied a simple structural concept of three elements: columns, rings and braces, to this more complex geometry.The waist of the tower contains a 180 m (590 ft) open-air skywalk where visitors can physically climb the tower.

There are outdoor gardens set within the structure, and at the top, just above 450 m (1,480 ft), a large open-air observation deck.The interior of the tower is subdivided into programmatic zones with various functions, including TV and radio transmission facilities, observatory decks, revolving restaurants, computer gaming, restaurants, exhibition spaces, conference rooms, shops, and 4D cinemas.

A deck at the base of the tower hides the tower's functional workings. All infrastructural connections – metro and bus stations – are situated underground. This level also includes exhibition spaces, a food court, a commercial space, a parking area for cars and coaches. There are two types of lifts, slow-speed panoramic and high-speed double-decker.The zone from 80 to 170 m (260 to 560 ft) consists of a 4D cinema, a play-hall area, restaurants, coffee shops and outdoor gardens with teahouses. An open-air staircase, the Skywalk, starts at the height of 170 metres and spirals almost 200 metres higher, all the way through the waist.

The top zone of the tower begins above the stairway, housing various technical functions as well as a two-storey rotating restaurant, a damper and the upper observation levels. From the upper observation levels it is possible to ascend even higher, via a further set of the stairs, to a terraced observation square rising above the tower's top ring.

Architectural Lighting Design
At night, the tower glows and emits light, rather than being uplit. Every node in the lighting design is individually controllable to allow for animations and colour changes across the entire height of the tower. As all lighting is based on LED technology and all fixtures are located on the structure itself, the lighting scheme consumes only 15% of the allowed maximum for facade lighting.

Canton Tower has architectural lighting that was designed by Rogier van der Heide. The architectural feature lighting is based on the principle that the tower should not be "lit up" but "radiate a glow" at night. 7,000 LED light fixtures light the rings of the tower's structure each from underneath, to form a continuous glow.