Work on the GBP1.5 million artwork was sub-contracted to AK Heavy Engineering by the main steelwork contractor, Westbury Structures, thanks to the Sheffield company's exceptional fabrication and machining resources, its pool of skilled craftsmen, tremendous heavy lifting capacity and a proven logistics capability for transporting large steel structures. The core of the sculpture, which itself will weigh around 80 tonnes and occupy a space envelope of 10m long x 5m wide x 4m high, will be shipped in one piece to Manchester. Engineering design for this huge artwork, including computer analysis and scale models for wind tunnel testing, was the responsibility of Packman Lucas Consulting Engineers, while the overall project has been managed by Manage Limited.
The sculpture was commissioned by New East Manchester, the second urban regeneration company to be founded in the UK, and Thomas Heatherwick's design was selected following an international competition. The starburst design features 180 tapered steel spikes that are connected together at a central point, 22 metres above the ground, and the whole structure will be tilted at an angle of 30 degrees, considerably more than the Tower of Pisa in Italy. It symbolises the burst of speed and energy of an athlete launching out of the blocks and the title was inspired by Linford Christie, who famously started his gold medal winning Olympic 100 metres race 'on the B of the bang'.
"This piece of art is dramatic and unique," said Tom Russell, Chief Executive of New East Manchester. "It will create a new imprint on the skyline of east Manchester that will complement and enhance the impressive City of Manchester Stadium."
The grade of steel specified for constructing B of the Bang, known as Cor-Ten or weathering steel, is the same material used for another notable British sculpture, Anthony Gormley's Angel of the North, and some of the lessons learned when fabricating that structure were taken into account in the welding processes employed by AK Heavy Engineering. A high tensile, low alloy steel, Cor-Ten contains copper that, through the careful control of steel chemistry and the addition of other elements, yields exceptional corrosion resistance, at the same time producing an attractive purple-orange surface patina, which is much prized by artists. Over the years, the Angel has developed an attractive, uniform rust colour, with no visual difference between the welds and the weathering steel, and B of the Bang will eventually have the same appearance.
The structure has been designed by Packman Lucas for indefinite life and takes into account extreme wind conditions that may occur over the next 50 years. Analysing stresses within the structure at the design stage and using wind tunnel testing of a scale model were essential for providing an inherently safe structure and the very latest computer technology was used to determine the fabrication method and assembly sequence. Although traditional manufacturing drawings were used for the construction of the core, computer-generated 3D graphic images assisted AK Heavy Engineering in understanding how each individual spike had to be profiled and positioned. This was critical, as any single point within the 10m x 5m x 4m core had to be positioned within + 20mm diameter tolerance, equivalent to a five pence coin.
Westbury Structures supplied the spikes for the core structure as half steel pressings, which were welded together to form complete tapering tubes, no two of which were alike in shape or size. Once the prefabricated spikes, ranging in length up to 9m, had been thoroughly tested by ultrasonic and magnetic methods, they were individually cut to shape to fit the central core. The computer model produced paper templates, which were actually wrapped around the spikes so as to transfer the exact pattern by punch-marking, and the profiles were cut using conventional oxy-propane cutting torches, then hand ground for an exact fit.
AK Heavy Engineering fabricated the core structure on a custom-made jig, complete with scaffolding at various levels to provide access for craftsmen. Welding was carried out using three main processes: submerged arc welding, the most efficient and environment-friendly method, for the prefabricated spikes; flux core arc welding for joining the spikes to the core; while manual metal arc welding was employed where access was extremely limited. Specially adapted welding torches were needed for the more difficult joints and, since some parts were particularly inaccessible, left-handed welders were at a premium.
After consultations with experts in welding technology and through reference to the Angel of the North, AK Heavy Engineering established that a welding consumable containing an additional 2% nickel was needed to avoid possible micro-cracking, without impairing the distinctive patina of weathering steel. Such is the success of this approach, that not a single crack has been detected in over 5,000 hours of welding, at Sheffield.
The 80 tonne core structure, complete with five tapering, solid steel legs, will be shipped by AK Heavy Engineering to Manchester, where it will be installed in reinforced concrete foundations by Westbury Structures. Then a further 180 tubular spike extensions, also fabricated in Sheffield, will be delivered for bolting to the core structure, to complete the starburst effect. Cor-Ten steel covering plates will conceal the flanged connections between the core spikes and these tube extensions, to create seamless, continually tapering offshoots, with a uniform patina.
Floodlit at night for maximum impact, this impressive and structurally challenging sculpture will be a lasting tribute to the success and excitement of Manchester's Commonwealth Games, one of the country's foremost young artists and a winning combination of traditional and computer-aided British engineering skills.
ENDS
For further information, please contact:
Media: David Gent, David Gent Creative, UK. Tel: +44 (0)1706 220388, Fax: +44 ( 0)1706 215849, Email: david@davidgent.com
Other enquiries: Gordon Scott, AK Heavy Engineering, Sheffield, UK. Tel: +44 (0)114 291 4030
Aker Kværner ASA
is through its subsidiaries and affiliates ("Aker Kvaerner") a leading global provider of engineering and construction services, technology products and integrated solutions. The business within Aker Kvaerner spans a number of industries, including Oil & Gas production, Refining & Chemicals, Pharmaceuticals & Biotechnology, Mining & Metals, Power, Pulping and Shipbuilding. Aker Kvaerner has aggregated annual revenues of approximately USD 6 billion and employs around 29,000 employees in more than 30 countries. The Aker Kvaerner group consists of many legally independent entities, constituting their own separate identities. Aker Kvaerner is used as the common brand or trademark for most of these entities.
AK Heavy Engineering
combines the expertise of two of Europe's largest and best equipped manufacturing businesses, Kvaerner Metals Davy Limited and Kvaerner Markham. The integration of these two long established engineering and manufacturing resources gives unparalleled experience and capacity to satisfy the demands of clients for medium, heavy and critical equipment. The Sheffield-based business spans a number of industries including: - mining and metals, nuclear, hydropower, and general engineering.
This press release may include forward-looking information or statements and is subject to our disclaimer, see our web-pages www.akerkvaerner.com