Raising the roof in Wisconsin

Overview ALE has successfully lifted the entire roof structure of a large Auditorium in Madison, Wisconsin, a project for which the company has just received the 2013 Project of the Year Class III award from the Steel Erectors Association of America. The project, which was engineered in three phases, used a method of erection that removed the need for multiple shoring towers and guy ropes, making the infield usable for sub-assembly and construction. The first phase involved lifting the 4,000ft roof in small increments to determine how the structure behaved when suspended, and assess for any necessary adjustments. The roof was then lifted approximately 60ft to 10 ft above its final elevation. Sixteen 400t Strand Jacks were mounted on the steelwork on the perimeter of the roof and four 600t Strand Jacks were installed in pairs on the inside truss section. Each pair was linked hydraulically forming one single 1200t Jack at two locations. All 20 of the lifting jacks were synchronised to within half an inch of each other, maintained throughout the lift by the hydraulic synchronisation between the power pack and the jacks. The computer system closely monitored loadings and jack extension on each jacking point. Two permanent roof support columns under the roof were then installed and the roof was lowered 10ft to its final elevation. The perimeter was lowered to line up with bolt up connections at each of the 16 points using more than 1000 bolts. Using this method of roof erection, ALE was able to improve safety, and save man hours, equipment rental and weather losses.

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