People have always got used to seeing TV towers as antennas with hierarchical lattice metallic wireframe. the Canton Tower is the first parametric TV tower ever designed.

Courtesy of Frank Kaltenbach.

Courtesy of Frank Kaltenbach.

The tower is located in Guangzhou’s Haizhu district at the intersection of the New Central Axis with the Pearl River. It was opened to the public in November 2010 at the same time as the Asian Games Opening Ceremony in China. The design of the building was chosen through an international architectural design competition in 2004. Famous senior architectural offices and firms participated in the competition and Information Based Architecture (IBA), a Dutch architecture office based in Amsterdam won the contest with a design that symbolizes the trend of Guangzhou city towards challenges and modernity.

Courtesy of IBA.

Courtesy of IBA.

Building Background

The design competition did not only call for a tower’s design, but also the design of a 17.9 ha park and a 56.6 ha master plan that includes an elevated plaza, pagoda park, retail facilities,  offices, television center and a hotel.

Courtesy of CTBUH - Photographer Terri Meyer Boake

Courtesy of CTBUH – Photographer Terri Meyer Boake

Construction Commission of Guangzhou Municipality chose IBA’s design for its  elegance, beauty, and its hi-tech features. IBA’s initial concept design was simple. It’s cylinder that was tapered and twisted counter clockwise to model a feminine graceful sculpture. Therefore, the tower carried several names such as Supermodel and “Xiao  Man  Yao” which means “Young girl with tight waist”.

Courtesy of IBA.

Courtesy of IBA.

The tower rises 600 meters with 454-meters height allocated for 37 storeys and 146 meters for the antenna. The building has a multifunctional program, which includes exhibition spaces, a conference  centre, a cinema, several restaurants, cafes and observation decks. It is divided to three main zones:

Base Zone

It contains all infrastructure services of the tower, in addition to metro and bus stations. The entrance has two levels, one opens to the park and the other serves the underground transportation and the 600-vehicle parking lot. This zone also includes a museum, food courts, stores, and slow and high-speed lifts.

Middle Zone

It starts from the height + 80 m to + 170 m and contains 4D cinema, play areas, restaurants, coffee shops, and outdoor balconies.

Top Zone

It includes the technical services and mechanical equipments such as Dampers. It also contains a two-storey rotating restaurant and an observation deck.

Courtesy of IBA.

Courtesy of IBA.

Courtesy of IBA.

Courtesy of IBA.

Building Context

The purpose of IBA design of the tower was to have an unfamiliar geometry for a TV tower. They wanted to design a funky skyscraper that is friendly and welcomes the people of Guangzhou city to visit and have fun. They made the tower a place of pleasure and enjoyment by providing it with entertainment services such as the Skywalk. The skywalk are a hanging gardens vary in term of atmosphere, lighting, and views. They also designed an open spiral staircase between +170 m level and +350 m. the visitors can enjoy the scene of the lattice structure from inside and the beauty of the waist’s shape.

Courtesy of IBA.

Courtesy of IBA.

The tower was also provided with observation boxes at the levels + 32, +116 as outdoor gardens, and at the levels +168, +454, +459 as indoor gardens. They are glass boxes extend out of the tower geometry to give the visitors the ability to enjoy the scene of the city under their feet.

Courtesy of IBA.

Courtesy of IBA.

The roof of the tower is used as an observation deck. It has a sloping oval shape that was tapered diagonally towards the North-West axis. The visitors can sit on this slope and enjoy the view of the old city from 460 high. They can take a ride on the world’s highest horizontal Ferris wheel Bubble Tram that is moving along the perimeter of the deck.

Courtesy of IBA.

Courtesy of IBA.

Overview of Parametric Design

The designers Mark Hemel and Barbara Kuit were determined to design the tallest, most feminine TV tower in the world. Barbra said “Where  most  skyscrapers  bear  ′male′  features, such as being, introvert,  strong,  straight,  rectangular,  and  based  on  repetition,  we  wanted  to  create  a  ′female ′  tower  being  complex,  transparent,  curvy  and  gracious. Our  aim  was  to  design  a  free-form tower  with  a  rich  and  human-like  identity  that  would  represent  Guangzhou  as  a  dynamic  and exciting  city. We  therefore  wanted  it  to  be  non-symmetrical  so  that  the  building  would  look  as if  ′in  movement′  and  ′alive′. The  result  is  a  tower  like  a  ′sexy  female′,  the  very  reason  that earned  her  the  nickname:  ′Xiao  Man  Yao′.″  which  means  “young  girl  with  tight  waist”

Courtesy of CTBUH - Photographer Tansri Muliani.

Courtesy of CTBUH – Photographer Tansri Muliani.

The credit of the successful design and implementation goes to the parametric softwares, which facilitated the design process and made it easy and flexible. The design company has adopted the latest technologies in the field of design, environmental analysis, and fabrication to design a successful sustainable timeless tower.

The Geometry

The design concept was born simply and unexpectedly where Mark tied two wooden trays with elastic rubber bands, and when he suddenly rotated the upper ellipse by 45 degree, a beautiful shape was created.  The owner of the project was impressed with the geometry and challenged the designers to focus on the waist and tightening it as much as possible. It was a great challenge due to the difficulty of preserving the mass balance at this critical area, and to fit all functions in this narrow floor, like the elevators, stairs…etc.

Courtesy of IBA.

Courtesy of IBA.

The modeling process of this double-curve surface required a number of operations. First, the elliptical cylinder was tapered to be narrow at the top. Then, the vertical elements were rotated to create the tightness and the upper profile was twisted more for further tightness. After obtaining the desired geometry, the solid was converted to a 3D wireframe for structural analysis. The surface was transformed to columns, diagonals, rings, and nodes. Consequently, a balanced lattice structure was produced. The structure consists of 1100 steel nodes, 1100 rings, and bracings. Overall, the resulted construction is formed with 3300 structural elements; each element is unique with its design, shape, and measurement. “Recent  State  of  the  Art  fabrication  and  computerized  analysis  techniques  allow  designers  to create  much  more  complex  structures  than  ever  before.” Mark thanked the fabrication technology for the success of the tower implementation.

Courtesy of IBA.

Courtesy of IBA.

 

The Structural Design

The Canton Tower’s structure consists of two tubes, one inside the other. The inner tube is represented in the elliptical reinforced concrete core. The core contains the lifts, fire emergency elevators, stairs, and the shafts. It consists of 37 reinforced concrete floors varying in design, area, height, and functions. Whereas the outer tube is defined with the lattice grid that consists of columns, diagonals, rings, and nodes. They also differ in their horizontal sections, shapes, and designs, which gave the tower its feminine distinguished form. Here is a detailed explanation about the structural elements:

Columns

There are 24 hollow steel pillars filled with concrete. At the tower base, the diameter of the columns is about 2 meters with 50 mm thick steel plate. The length of each piece of the columns ranges about 3.7 meters, which are then bolted and welded. At the top, the diameter decreases to 1.1 m and 30 mm thick steel plate. The accuracy of the installation reached 1l2000 whereas the error did exceed 5 mm.

Courtesy of Frank Kaltenbach.

Courtesy of Frank Kaltenbach.

Diagonals

The diagonals are the structural elements that intersect diagonally with the columns to create the lattice web. The diameter of the diagonals is fixed at 800 mm.

Rings

The rings were added to the structure as supportive elements for the lattice web. They were inserted and hide inside the structure to reinforce the columns and the diagonals through the nodes. The rings were tilted 15 degree to be more consisted with the form. They also vary in their horizontal profile according to their positions in the web.

Courtesy of IBA.

Courtesy of IBA.

Nodes

The design of the nodes was the biggest challenges for the designers. There are 1100 nodes for the 600 m height structure and each node is unique with different size and details.

Foundations

The groundbreaking ceremony of the tower took place after a year of installing the foundations. Twenty four piles were dug at 40 meters in the ground with a 3.8 m diameter.

Courtesy of Frank Kaltenbach.

Courtesy of Frank Kaltenbach.

The Antenna

The antenna rises 150 meters above the observation deck. It has an octagonal cross-section, and it was manufactured to two pieces; the thinner piece rises 80 meters, and it was constructed inside the wider one. The complete installation of the antenna was accomplished with the positioning of the upper piece in May 2009.

The Outwear

The outwear of the tower was made of a high-strength anti-explosion laminated glass. Each piece of the glass has its specific design and size and were all gathered to create the ruled surface.

Courtesy of IBA.

Courtesy of IBA.

The Fabrication

Because of the curved surface, none of the 10,000 structural elements are the same. This made the construction process difficult and required a high level of accuracy. All nodes, columns, and diagonals were prefabricated at a factory in Shanghai. They were all delivered by trucks and installed on site. At the beginning, the tubes of the columns were bolted. After completing the assembly operation, the columns were welded, and then the bolts were burned off. For more stability, the concrete was poured inside the steel hollow columns. It also provides more protection against fire accidents.

Courtesy of IBA.

Courtesy of IBA.

Courtesy of IBA.

Courtesy of IBA.

Written By: Sara Ben Lashihar

  • Canton Tower official Website. http://www.cantontower.com/en/

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