The new airport passenger bridge at Gatwick Airport, UK, is designed to take 3.5m passengers per year over a busy aircraft taxi-way to the new Pier 6 satellite building. The fully enclosed footbridge spans 128m across the taxi-way with a clearance height of 22m and is supported on two steel pylon structures. The bridge was assembled off site and installed using strand jacks during a 10 day closure of the taxi-way. DLT were responsible for the conceptual and detailed design of the temporary erection gantries required to construct the bridge.
The bridge superstructure was fully assembled at ground level in a temporary construction area 1.5km from the site. The central 175m long section weighed 2,185 tonnes, including the steel frame, composite floor, roofing system, glazing and services. The two erection gantries were assembled around the bridge superstructure in the temporary construction area and then load tested to 115% the maximum lift weight using the self weight of the bridge and the temporary assembly foundations. The gantries were then used to lift the bridge superstructure 1.5m to allow self propelled modular trailers (SPMT's) to be positioned under the bridge. The bridge and gantries were then transported together across the airport to the final location on the SPMT's. The gantries were then lowered onto prepared foundations ready for lifting the bridge. Eight 418 tonne capacity strand jacks mounted at the top of the two gantries were then used to lift the bridge to approximately 2.4m above final level to allow installation of the pylons beneath. The two pylons were hung from the underside of the bridge and the complete assembly, weighing 2,660 tonnes was then lowered by the strand jacks onto the permanent foundations. The gantries were then dismantled and removed from site