THE ROYAL Engineer's General Support Bridge, a steroid-fed mobile structure, was on show at Civils 98 and it is returning to Birmingham this year for Civils 2000.
At 35m long, the GSB can carry a 70t tank. It is transported on three, eight axle trucks with a combined weight of 90t.
But the colossus takes only 45 minutes to erect. Crowds at Civils 98 were enthralled as a team of REs raced against the clock to assemble the bridge. This year's visitors will be able to see if the REs can beat their best time - demonstrations are being staged on each of Civils' four days.
The GSB is a modular structure, with box section elements in 2m, 4m and 8m lengths, and a pair of 8m ramps carried on two of the trucks. Elements are hauled to position along a telescopic carbon fibre boom mounted on the third vehicle, and pinned together.
When the span is completed the whole is lowered to support its own weight and the boom retracted.
A 50m model of the GSB is currently being developed, said a RE spokesman. To improve strength to weight ratios over longer spans, posttensioning cables are being added into the structure.