CCTV Towers, Beijing, China
China’s current building boom is doing more than sucking up the world’s supply of steel – it’s a stage for some of today’s boldest architecture and engineering. The new China Central Television Headquarters building is like an upside-down asymmetric U involving two L shaped high-rise towers linked at the top and the bottom at an angle to form a loop. It will consist of a series of horizontal and vertical sections establishing it as an earth bound structure and not a traditional skyscraper. The project is planned for completion to broadcast the Beijing Olympics in 2008. Its development has been undertaken by the Chinese Government as part of a plan to redevelop central Beijing with innovative and functional architecture, while preserving historic buildings at the same time.
The total construction cost is estimated at 600 million euros. The tallest tower will be 230m high with a floor area of 405,000m². The building is set to break the Chinese design codes, but this was expected for such an innovative design, because of which the project is very complicated and requires management expertise as well as expertise with mechanicalelectrical systems, steel, and high rises. The structure of the building is a challenge to the engineering contractors, who need to design a plan to construct the two 60° leaning towers that are bent at 90° at the top and bottom. The engineers’ solution is to create a structural ‘tube’, a diagrid ‘exoskeleton’ of diagonal supports, on the external faces of the building to give a structure that will resist gravity and any lateral forces.
The structure is in fact so complex that the designers have not been able to imagine the shape in their minds to do the connection design. The Tekla 3D model is used for the connection design and erection phases of the project. Designers model the connections in Tekla Structures to find out the actual shape of the connections, and then do the calculation. After that, they do the detailing with Tekla Structures, creating assembly and single-part drawings for fabrication. The connection design also involves seismic design, as there are strict seismic requirements for Beijing buildings that have to be met. Thin concrete cores inside the building will support the internal floors. The steelwork contractor supplied 120,000 tons of steel on this project.
Khalifa Sports City Tower, Doha, Qatar
Also known as the Aspire or Flame Tower, this is a 318 meter structure located in the Sports City complex of Doha. The tower served as the focal point for the 15th Asian Games in December 2006 and is the tallest structure in Doha for the time being. Due to its size and proximity to the main venue, the Khalifa International Stadium, the tower was a landmark of the Games and served as a torch for the Olympic flame.
The interior of the tower is expected to be fully completed by the end of 2007. Upon its completion, the tower will include a five-star hotel. Inside the curved glass outer shell, four distinct circular structures are grouped around the central tower. The central spine of the structure provides quick access to the other segments of the building. The tower is surrounded on all sides by flat terrain and desert, which means that there can be significant wind loads placed on the structure, not to mention the risk of sandstorms and vast temperature differentials of +5ºC on a winter night to +85ºC in the peak of summer.
The exterior of the building is covered in a steel mesh which, during the Asian Games, was illuminated by LED lights. A more solid outer cladding would not offer the same lightweight tolerance and such a tall building would have to sacrifice some of its slenderness to withstand the natural extremes placed on it. These stresses are substantially reduced by the lack of solid cladding covering the main bulk of the building, allowing the metal fabric to pass wind and sand through it whilst giving some measure of protection to the central concrete core, which acts as the primary support.
The remainder of the building is a steel structure that cantilevers out from the concrete core. The building has been constructed to very high standards and specifications and incorporates top-quality finishes. Wind tunnel testing has been conducted to ensure the safety of the structure.
Ski Dubai, UAE
A unique mountain-themed attraction, Ski Dubai is the first indoor ski resort in the Middle East. It is located inside the Mall of the Emirates and offers a 3000 square meter indoor snow setting for skiing, snowboarding, and tobogganing – an opportunity to enjoy real snow in the desert all year round. Tiger Steel Engineering used Tekla Structures for steel detailing to complete the complex and stately snowdome structure with excellent results.
Built like an upside-down letter L, with its highest point towering 85 meters above the main highway, the snowdome has a diameter of more than 200 meters (total area 22,500 square meters, including 25 stories of indoor slopes). The longest run is 400 meters, with a vertical drop of more than 60 meters.The runs have a 60 degrees curve on the way down to make them more challenging. For snowboarders there is a 90-meter quarterpipe and what is claimed to be the 
largest indoor snow park in the world.
Tiger Steel had two experienced detailers working on the complex phase 3 of the Ski Dubai project. Without using Tekla Structures, they would have needed around ten detailers and the detailing phase would have taken two months longer. According to the company representative, Tekla Structures provided time savings, error-free details and 100% accuracy. Integration of the software with the existing working environment was easy.
North East Tower Center, Padua, Italy
The new tower of the Padua NET Center complex, with 20 floors and 80 meters in height, is set to become a point of reference in the city’s landscape. The architectural approach to the design of the buildings hinges around an open space with maximum visibility of the structures, and steel has been selected as the most suitable construction material for this purpose. Modeling the steel structures with Tekla Structures helped achieve the architectural objectives for the building, which would otherwise have proven difficult from the technical viewpoint.
The tower columns and girders were modeled using Tekla Structures. The column joint was realised during construction using complete-penetration welding. The welded girders for the 20 floors were joined to the columns by means of bolted joints. Processing speed was not the only benefit arising from the use of Tekla Stuctures; the software also allowed to correctly and precisely set the angle for the entire structure during the mounting stage. The lower building, ‘Palazzo Tendenza’ is characterised by a precise and linear design, conferring the palace an elegant and essential shape. Made of steel and glass, it consists of about 13,300 total floor surface distributed in five levels.
On the inside, the palace is full of light. The main space is a long and wide “gallery” where all the units of the building are linked by steel walkways. The two main elevations of the building are almost entirely made of glass. Besides the external curtain-wall, there is one more shell made of grey steel brise-soleil to protect the internal spaces from sunlight. The tower will host a hotel and offices. Its floors have a trapezoid shape that changes on every level and forms ruled surfaces on the façade. The regular horizontal lines of the red steel shading protect the external glass façade from the sun. The structure of the tower consists of an internal concrete kernel, and the light concrete slabs “hang” from this core.
Swan Bells Tower, Perth, Australia
When the weight of the twelve bells of London’s St Martin’s in the Fields became too heavy for the aging structure of the church, it was decided to replace them with a lighter peal. The original bells were first cast in the 14th Century, six more have been cast especially to add to them and were presented to the City of Perth to mark Australia’s bicentennial in 1988. The Swan Bells Tower is now an architectural landmark and the bells have become a monument synonymous with Perth, the sound of its success ringing proudly through them.
Steelplan Australia worked with the architect to define the complex geometry of the tower and of the doubly curved sails. The Tekla Structures model they created was used to generate the information for the steel fabrication, the cladding and the glazing. This ensured that everything would fit together on-site. The building is actually two buildings joined together: a stout concrete bell chamber and a slender 82.5 m steel and glass octagonal spire, only 6.5 m in diameter at its base. The sail structures were fabricated from rectangular and circular hollow sections and clad with copper shingles. The spire steelwork was prefabricated in six segments. The tapered cylindrical upper tower was divided into three rises.
All work was done off-site to minimise setout problems and ensure the correct shapes and curvatures. The design required full strength butt-welded site joints but a bolted joint was developed for use at higher locations to avoid site welding. The glazing system details were developed to allow a compression-sealed joint at the bolted spire connections. These changes meant the spire could be constructed off-site in large modules and then fully glazed on-site prior to being lifted into place. A 400-ton hydraulic mobile crane (the largest in Western Australia) was used to complete the project. The chamber with its bells forms what is reported to be the largest musical instrument in the world.
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