[Video + images + drawings + credits] The team behind the ArcelorMittal Orbit, Anish Kapoor and Cecil Balmond with Ushida Findlay Architects and Arup, has risen to the challenge and integrated art, structural engineering and architecture writes Felix Mara
If the greatest achievement of the baroque was to integrate sculpture into architectural form, by incorporating architectural elements into Britain’s largest sculpture the designers of the ArcelorMittal Orbit will achieve the exact opposite.
This landmark feature of the London 2012 Olympics will open next year having received up to 86 per cent of its funding from ArcelorMittal, the world’s largest steelwork manufacturer. Ian Louden, head of worldwide brand at ArcelorMittal, says that the competition to design the sculpture was initiated by Boris Johnson because the mayor of London thought the buildings originally proposed for the Olympic Park, lacked the ‘wow factor’.
Of the 26 competition entries, the preliminary design for the Orbit, by sculptor Anish Kapoor and structural engineer Cecil Balmond of Arup, stood out as the best response to the brief for a ‘world class’ structure which visitors could interact with during the Games and for years afterwards.
Structural design
The sculpture’s sophisticated design is cleverly integrated with its overall concept, which Daniel Bosia, who worked on the project as a member of Arup’s Advanced Geometry Unit (AGU), says was inspired by the idea of ‘an orbit in space’. The below video, by Bosia, shows the ‘Genesis of the Form’.
‘We want people to forget the engineering, the construction, the materials and simply “experience” it,’ says Balmond. ‘All tower structures are pyramidical, but we wanted to see if we could create a structure with a non-linear form – an orbit that turns and gathers strength from each loop.’ The principal structure comprises a tower with an octagonal plan form stabilised by two large, writhing tentacular elements with twisting, square cross-sections, which the designers refer to as ‘intestines’. Like these intestines, the tower is a steel diagrid structure with CHS components and it supports a tuned mass damper that helps to resist wind loads.
Integration of architectural elements
Visitors to the Orbit can take a lift that rises through the tower to an enclosed, high-level observation deck, returning to earth via a helical staircase with 455 steps and, after selecting the Kapoor and Balmond design, ArcelorMittal appointed Ushida Findlay Architects to develop these components. ‘Cecil felt I had an understanding of non-rectilinear geometry,’ says Kathryn Findlay. Although the London practice’s remit included the design of the entrance pavilion, the plant compound, a ramp and a high-level external walkway, its overarching brief was to ensure that public spaces were not only habitable but also comfortable and fully integrated with the overall design, effectively transforming the sculpture into an accessible architectural experience.
Ushida Findlay project architect Thomas Van Hoffelen, explains that the architectural components are combined with the principal structure through the use of ‘contrasting geometries’. The use of finishes and textures also serve this end. Stainless steel expanded metal with a graded opacity has been used to clad the staircase and ramp, leaving the ruby red steelwork visually intact. ‘There was a lot of work to do where structure meets architecture and where services are brought in,’ adds Carl Johannsen-Ward, who is leading the project for the architect.
Design and construction process
The design and construction process was itself almost a monument to its time. Its sophisticated computational design is described by Bosia as ‘a systematic, forensic, real-time “form-finding” process capable of stretching the structure to its limits through the use of custom-made, parametric design and analysis tools developed by the team’. AGU used Rhino, with Grasshopper, a parametric plug-in. GSA was used for the structural analysis while steelwork manufacturer Watsons used Tekla solid modelling software to calculate section sizes.
The design and build procurement process is also very much of its time. ‘We defined the design intent for each connection,’ says Holger Falter of Arup. ‘No drawings were provided,’ he adds, but Watsons rose to the challenge and worked with what seemed impossible tolerances. ‘This wouldn’t have been possible 20 years ago,’ says ArcelorMittal’s chief project engineer, Pierre Engel.
The Orbit appears more virile and expressive rather than graceful, yet its anthropomorphic qualities and elegant interventions will make it a fitting addition to the Olympic Park.
Start on site November 2010
Contract duration 17 months
Gross internal floor area 920m 2
Form of contract NEC3 Construction Management
Total cost £22.5 million
Cost per m 2 N/A
Client ArcelorMittal
Architect Ushida Findlay Architects
Structural engineer Arup and Advanced Geometry Unit/Arup
M&E consultant Arup
Planning consultant Arup
Quantity surveyor Davis Langdon
Lighting consultant Arup
Acoustics consultant Arup
Project manager Davis Langdon
Main contractor Sir Robert McAlpine
Cladding contractor Lindner Facades
CDM co-ordinator Arup
Approved building inspector JLAB
Estimated annual CO2 emissions 34.3 kg/m 2