Curves result of latest hi-tech

MAIN contractor Dragages et Travaux Public used the latest computer and drafting technology to ensure that hundreds of elements of the new stadium, all of slightly different sizes, slotted perfectly into place on time.

With this latest technology, Dragages could ensure all the bleachers, beams and planks - each slightly bigger or smaller than its neighbour because of the stadium's parabolic shape - were accurately formed.

Dragages worked closely with British engineers Ove Arup and architects Hellmuth, Obata and Kassebaum of the United States (HOK) to craft the stadium from grand plans.

Sometimes there were clashes, but these animated discussions had the benefit of bringing everyone together in a cohesive effort to get the job done.

From the start, Dragages realised that the only way it would deliver the cost and time savings it promised was to prefabricate all of the main concrete structures.

''All of the form work used to make the concrete moulds was designed by our head office in France,'' said Henri Paoli, the Dragages project manager.

''The computer system was so sophisticated that as each set of beams and planks was installed it could amend the design to take account of any changes.'' Every night the site computer system was linked to Dragages' main computer network in France to ensure that proper quality control was maintained.

Another critical phase was when the steel roof trusses were fixed to the top of the rakers last year - after construction was halted temporarily for the Rugby Sevens and Viceroy Cup soccer final.

Dragages had already redesigned the roof system to reduce the amount of steel when it submitted its alternative proposal to the Jockey Club in 1992, but the computer-based drafting allowed even tighter specifications to be achieved.

''When we connected rakers via the steel roof trusses to the main arches, the margin of error was just three to four millimetres,'' Mr Paoli said.

But Dragages did not haveit all its own way.

It originally wanted to change the shape of the rakers.

Ove Arup, however, refused even though it recognised the concrete would be more difficult to pour and the softer oval lines harder to achieve.

The often difficult relationship all three had during construction, began at the launch of the project when Dragages told the Jockey Club it could slash costs by completing the scheme in two years instead of three.

But, in return, it demanded more control over the architect and engineer to ensure these savings were achieved.

This news was greeted with anger by HOK and Ove Arup, who saw their responsibilities being usurped by Dragages.

''There were some spectacular rows,'' admitted Sandy Eeds, director of HOK's sports facilities group.