Taxiway 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 pounds (166,000 kg), but aircraft weights doubled within two years of its construction. Currently the Airbus 380 is the world's largest airplane in operation, with maximum take-off weight (MTOW) of 575 t (1,268,000 lb). The largest Boeing planes, i.e. the current "Project Ozark" versions of the Boeing 747-8, are approaching MTOW of greater than 1,000,000 lb (450,000 kg). 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:

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

The Port Columbus Airport Crossover Taxiway Bridge is an aircraft taxiway bridge at Port Columbus International Airport in Columbus, Ohio that was completed in 2008. It is a 24-cell box-girder bridge that spans the primary entrance roadway to the airport terminal. The taxiway bridge would allow aircraft to travel from the main terminal building to new outer runways of the airport. The bridge has a single 191 feet (58 m) span, is 217 feet (66 m) wide and is designed to carry a 747-400 aircraft weighing 894,900 pounds (405,900 kg). In order to fulfill the load requirements of large aircraft, the bridge design employs a post-tensioned cast-in-place concrete structural system with integral abutments. To keep the deck free from ice in winter a hydronic anti-icing system consisting of tubes containing glycol from a pump and heater is embedded into the deck.

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