2005 winners Mammoth bridge movement
30 April 2008
The British Airports Authority's plans to upgrade London's Gatwick airport called for a passenger bridge over an aircraft taxiway between a terminal and an aircraft loading pier. Th is was only the second bridging of a taxiway; the first was in Denver, Colorado.
To minimize disruption to the UK's second busiest airport, the construction program called for fabrication of the air bridge structure–810 feet long by 98 feet wide by 49 feet high and weighing 3,168 tons–off–site. It was then transported to Gatwick and lifted into final position overnight, when the aircraft taxiways could be closed.
The contract for the construction of the air bridge was awarded to Watson Steel, of the UK, which sub–contracted transport and lifting to Fagioli PSC.
The initial phase of the work required on–site assembly of Fagioli's PSC Lifting System, comprising standard Fagioli PSC Towerlift masts and strand jacks. Assembly took two weeks, after which a test lift of 3,600 tons was made.
Due to the limited time available for the transport and lifting operations, it was necessary to transport both the 548 feet, longest section of the air bridge and the supporting gantry together. Th is meant a total payload of 2,174 tons, requiring a total of 120 axle lines of Fagioli PSC self–propelled modular transporter (SPMT) and making a total convoy weight of 3,748 tons. The transport arrangement used to move the bridge and lifting towers combination to the final location comprised two sets of 60–axle lines of SPMT.
Precision of the final position of the bridge was ±1 inch at each end. Access to final position required a 90–degree turn of the transport rig, and two terminal connection piers at each end provided very little clearance. Because minor differences in steering alignments of the two transporter groups could create enormous torsion forces over the 548–foot span, a tubular restraint system was designed and installed between each trailer group and the bridge.
The bridge was already fully glazed and painted when moved over the 0.62–mile journey from construction site to final destination. Consequently, convoy length and width were continuously monitored and maintained to within ±2 inches in order to minimize any stresses