Aircraft bridge

Aircraft bridges, including taxiway bridges and runway bridges, bring aircraft traffic over motorways, railways, and waterways, and must be designed to support the heaviest aircraft that may cross them. In 1963, a taxiway bridge at Chicago O'Hare Airport, one of the busiest airports in the world, was planned to handle future aircraft weighing 365,000 lb, but aircraft weights doubled within two years of its construction. Currently, the largest passenger aircraft in the world, the Airbus A380, has a maximum take-off weight (MTOW) of . The largest Boeing planes, i.e. the current "Project Ozark" versions of the Boeing 747-8, are approaching MTOW of greater than 1000000 lb. Aircraft bridges must be designed for the substantial forces exerted by aircraft braking, affecting the lateral load in substructure design. Braking force of 70 percent of the live load is assumed in two recent taxiway bridge designs. And "deck design is more apt to be controlled by punching shear than flexure due to the heavy wheel loads."

Taxiway bridges are unusually wide relative to their length, and aircraft loading cannot be assumed to be distributed evenly to a bridge superstructure's web, so different modeling is required in these bridges' structural design. In cold climates, provisions for anti-icing must be made. In the U.S., regulations of the Federal Aviation Administration must be met. And there are various other differences versus typical bridges covered by AASHTO standards.

A major issue is that closing an airport for construction even temporarily is impossible.

Major alternatives considered for construction of a taxiway bridge in 2008 were:
  • use of precast, prestressed concrete I-girders
  • use of precast, prestressed concrete box girders
  • use of steel girders
  • cast-in-place, post-tensioned concrete box girder bridge.

    Finite Element Analysis has been advocated for, or applied in, taxiway bridge design since at least 1963.

    List of taxiway bridges, runway bridges, and related tunnels

    Taxiway bridges and runway bridges are bridges at airports to bring airplane taxiways and runways across motorways, railroads, or waterways. A taxiway bridge must be designed to carry the weight of the maximum size airplanes crossing and perhaps stopping directly upon it. A runway bridge is similar but may have different stresses. Alternatively, a motorway may be brought by tunnel underneath one or more runways and taxiways. Examples include:
  • At Amsterdam Schiphol Airport, the 650 m Schiphol tunnel takes the A4 motorway underneath an airplane runway and two taxiways, and in 2003 a sixth runway was added at quite some distance west of the rest of airport, with use of two connecting taxiway bridges crossing the A5 motorway and the , respectively.
  • At Manchester Airport in the United Kingdom, the A538 road runs in a pair of twin-bore tunnels underneath the southern ends of both runways.
  • At Los Angeles International Airport, a tunnel was completed in 1953 allowing Sepulveda Boulevard to revert to straight and pass beneath the two runways; it was the first tunnel of its kind.
  • At Indianapolis International Airport, a taxiway bridge is planned to connect a future fourth runway across the Interstate 70. During 2002-04, the Indiana Department of Transportation realigned the I-70 to accommodate this.
  • The third runway of the Stockholm Arlanda Airport is reached from the main terminal area by taxiway bridges constructed to be able to handle the heaviest and largest airplanes in traffic.
  • The Orlando International Airport authority, planning for a future high-speed rail line, invested in extra length for its taxiway bridges over its southern airport access road.
  • The Singapore Changi Airport has two taxiway bridges spanning Airport Boulevard. These bridges required shields installed on either side to shield the road from the jet blast. Planning for it since the 1990s, the airport spent S$60 million in total in modifications to support the Airbus A380.
  • The Soekarno–Hatta International Airport has two taxiway bridges located in the southwest corner of the airport connecting the north and the south runway, a third taxiway bridge located in the north east corner is under construction and is scheduled to finish in 2018
  • the Copenhagen Airport has one runway and one taxiway running over the Denmark 221 road.
  • In Norway, Sandane, Trondheim and Tromsø airports have such bridges.
  • $35-million Taxiway Sierra Underpass reconstruction at Sky Harbor International Airport in Phoenix, Arizona included a $13 million five-span, cast-in-place, post-tensioned concrete box girder bridge. The airport also has the Taxiway Tango Underpass.
  • $10.5 million Port Columbus Airport Crossover Taxiway, at Port Columbus International Airport, Columbus, Ohio
  • Taxiway B Bridge, Tampa International Airport
  • Taxiway bridge over Interstate 73, Piedmont Triad International Airport, Greensboro, North Carolina
  • Five taxiway bridges, Beijing Capital Airport
  • 1967-built steel girder taxiway bridge, Chicago O'Hare International Airport In 1963, the weight thought to be necessary was 365,000 lb for the 1967 built bridge. In 1969, aircraft weights had doubled. It was a 4-span welded steel girder bridge with a concrete deck, 226 ft long, 125 ft wide, bridge. Maximum stress for the bridge was found to occur when an aircraft was 6 feet off the centerline.
  • Interstate 285 runs under a runway and taxiway of Atlanta's Hartsfield-Jackson International Airport (and see []?)
  • Tunnel Road East, the main entranceway to Heathrow Airport, runs under a runway and two taxiways
  • S. 188th Street runs under a runway and a taxiway of Seattle-Tacoma International Airport
  • Kai Tak Taxiway Bridge No. 3, a fast-track design-and-build contract awarded in 1993, at Hong Kong's Kai Tak Airport, which closed in 1998.
  • Fort Lauderdale-Hollywood International Airport has US Route 1 and an active railroad running under a runway and taxiway.
  • Düsseldorf International Airport has the approach end of runway 23L and the last taxiway out of the same runway 05R above a railway line. The Düsseldorf Airport Station offers a very good view of passing aircraft.
  • Hua Hin Airport's runway crossed over Phet Kasem Road (Thailand Route 4) and Southern Railway Line

    Numerous taxiway bridges have been proposed but not built.