Aircraft bridge
{{Distinguish|Jet bridge}}
File:Norwegian Air International Boeing 737 EI-FHV Stockholm Arlanda 2019 (01).jpg, Sweden]]
File:PH-BQP B777 KLM (5722702782).jpg, the Netherlands]]
Aircraft bridges, including taxiway bridges and runway bridges, bring aircraft traffic over motorways, railways, and waterways.
Construction
Aircraft bridges must be designed to support the heaviest aircraft that may cross them, or that will cross them in the future. In 1963, a taxiway bridge at O'Hare International Airport, one of the busiest airports in the world, was planned to handle future aircraft weighing {{convert|365,000|lb|kg}}, but aircraft weights doubled within two years of its construction.{{cite book |author1=O.C. Guedelhoefer |url=https://books.google.com/books?id=eVXu5XalHpcC&pg=PA18 |title=Evaluation of Performance by Full-Scale Testing |author2=J.R. Janney |publisher=American Society for Testing and Materials |year=1980 |isbn=9780803103689 |editor=W.R. Schriever |pages=17–19}} (book title is Full-Scale Load Testing of Structures) Currently, the largest passenger aircraft in the world, the Airbus A380, has a maximum take-off weight (MTOW) of {{Convert|575|t|lb|abbr=on}}.
The largest Boeing planes, i.e. the current "Project Ozark" versions of the Boeing 747-8, are approaching MTOW of greater than {{convert|1000000|lb|kg|abbr=on}}. 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.{{cite web |author1=Shane Johnson |author2=Tom Morrison |date=April 10, 2015 |title=Design and Construction of Micropiles Supporting Taxiway Bridge |url=https://connect.ncdot.gov/resources/Geological/Documents/6A-2%20Design%20and%20Construction%20of%20Micropiles%20for%20Taxiway%20Bridge_Johnson_Morrison.pdf}} 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.{{cite journal|journal=Aspire |title=A New Welcome at the Port Columbus International Airport |url=http://aspirebridge.com/magazine/2009Winter/port_columbus_win09.pdf |accessdate=17 May 2013 |author1=Kevin M. Gorak |author2=Troy D. Jessop |date=Winter 2009 |pages=34–37}} (with 4 pages of additional photos published in the web version){{rp|2–3}} In cold climates, provisions for anti-icing must be made. In the U.S., regulations of the Federal Aviation Administration must be met.{{cite journal|url=http://aspirebridge.com/magazine/2008Spring/taxiway_spr08.pdf |journal=Aspire |author1=Ted Bush |author2=Kent Bormann |author3=Rob Turton |title=Airport Bridges Take Off |date=Spring 2008 |accessdate=July 31, 2016 }}{{cite web|url=http://www.faa.gov/documentLibrary/media/Advisory_Circular/draft_150_5300_13a.pdf |title=Advisory Circular AC 150/5300-13A |publisher=Federal Aviation Administration |date=May 1, 2012}} And there are various other differences versus typical bridges covered by AASHTO standards.[https://www.acconline.org/Content/NavigationMenu/Resources/AgencyComments/AC15530013AirportDesign.pdf Anthony N. Mavrogiannis, of Airport Consultants Council, Review Comments on Advisory Circular 150/5300-13, Airport Design] {{Webarchive|url=https://web.archive.org/web/20131021071646/http://www.acconline.org/Content/NavigationMenu/Resources/AgencyComments/AC15530013AirportDesign.pdf |date=2013-10-21 }}, see esp. p.3.
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.{{cite book|author=Alan R. Jefts |year=1983 |title=Finite Element Analysis of a Taxiway Bridge |publisher=American Society of Civil Engineers |isbn=9780872623514 |url=https://books.google.com/books?id=qtlRAAAAMAAJ&q=Taxiway+bridge }} in book Proceedings of the Eighth Conference on Electronic Computation
{{anchor|Port Columbus Airport Crossover Taxiway Bridge}}
References
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External links
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- [https://web.archive.org/web/20160304060436/http://www.dot.state.oh.us/engineering/OTEC/2007%20Presentations/Tuesday/Sess34/OTEC%20Presentation_Jessop.pdf Port Columbus International Airport Cross-Over Taxiway Bridge Project]
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