Page 31

0603NSCMarch06

Leisure This page, clockwise from top left: Steel raking beams support the top level of seating and half of the lower level; Every bay has been temporarily braced; All the erection is being done using mobile cranes and cherry pickers; The cantilever sections are erected from the base of the stadium’s bowl Vinnicombe. “The steel has been beefed up in that ing that has been a constant element of the project FACT FILE area.” - the fabricator introduced the cheaper alternative of Milton Keynes So, despite the West stand being on the critical using welded plate girders for the 28m long raking Dons Stadium path, Rowecord had to start with the North and East beams. Main client: Inter MK Architect: HOK Sport Stands then move onto the more complex West and Plate girders have also been used for the tips of Structural engineer: South. the 31.8m long cantilever roof trusses. These canti- SKM The stadium, designed by HOK Sport, has two levers are erected in three sections. The first - at the Main contractor: tiers of seating all the way round, with a concourse back of the stand - go up as part of the initial frame Buckingham Group running the full circumference between the two. construction, working from within the floor plate of Contracting Unusually, the concourse is at ground level, with the the building. Then, the 14.2m long mid section and Steelwork contractor: pitch sunk in a 4m deep bowl and much of the lower 10.2m tip are erected from the pitch level. The upper Rowecord Engineering Project value: £42M tier of seating sitting directly on the banked sides of and lower chords of the cantilever trusses are made Steel tonnage: 4,300t the bowl. from 250 x 250 square hollow sections, while the in- As a result, the steel structure supporting the fill steel is 114mm diameter circular hollow sections. roof is much lower than in traditional two tier stadia, There is no tower crane on site, and all the steel- and both tiers can be accessed directly from the work has been erected using mobile cranes, with the concourse without the need for either stair towers or erectors working from cherry pickers. “We haven’t special access for the disabled. had anyone out on the steelwork yet,” says Mr Vin- The entire North and East Stands and half of the nicombe. “We’ve planned the whole project not just South have the lower tier of seating constructed around the fabrication and delivery to site, but also from in situ concrete placed on the banked sides of around the construction. Any big project like this has the bowl, and in all stands the upper tier consists got to be construction-led.” of precast concrete units supported by 1,020mm Rowecord must ensure the frame is stable deep steel raking beams fixed to the main structural throughout the construction process. Structural frame. For the West and half of the South Stands, engineer SKM’s design is based on the roof acting however, the lower tier of seating is also supported as a diaphragm, so it is not stable until the entire by raking beams rather than on the earth bank to ac- structure is complete. To compensate, Rowecord commodate the future arena and the hotel. is installing full height temporary cross-bracing in Rowecord’s basic frame consists of two columns every bay. On the West Stand, the lower tier of rak- with the floor steel spanning the 7.2m between ing beams also provide permanent bracing, so they them, a 9m long triangular backspan section at roof have to be in place before the front section of the level, and the first section of the cantilever roof and cantilever roof truss can be erected. a raking beam. In all, there are 50 of these frames Rowecord started work on site in mid-August around the outside of the bowl, placed on a 7.2m 2005 and will finish in April 2006, putting the scheme grid. on schedule for completion in time for the start of For the columns and the floor beams, Rowecord the 2006/7 football season. It remains to be seen if has stuck with standard universal beam and column Mr Winkelman’s dream will be realised, and the fans rolled sections. But - as part of the value engineer- will then come. NSC March 2006 31


0603NSCMarch06
To see the actual publication please follow the link above