Editing Box girder bridge (section)

{{short description|Type of bridge}}
{{ BridgeTypePix
|image=Concrete box girder bridge.JPG
|image_title=Underneath the [[No. 2 Road Bridge]] in [[Richmond, British Columbia]], [[Canada]]
|type_name=Box girder bridge
|sibling_names=[[jetway]], [[skyway]]
|descendent_names=[[segmental bridge]]
|ancestor_names=[[Tubular bridge]]
|carries=Pedestrians, automobiles, trucks, light rail, heavy rail
|span_range=Medium
|material=Steel, reinforced concrete, prestressed concrete
|movable=Possible
|design=High
|falsework=Yes, if cast-in-place reinforced or prestressed concrete is used, which is typical for freeway overpasses
}}

<!-- [[File:Hohlkasten.svg|thumb]] -->  
[[File:Zwillings-Hohlkasten_bzw._Twin_box_girder.svg|thumb|Section of a twin box girder bridge]]
[[File:Erskine Bridge.jpg|thumb|right|[[Erskine Bridge]], near [[Glasgow, Scotland]]]]

[[File:Swanport Bridge.jpg|thumb|right|Single box girder bridge ([[concrete]]), [[Australia]]. A similar bridge on this river was fabricated ashore and pushed across its pylons.]]

[[File:PlateBoxFlyover.jpg|thumb|right|Single box girder bridge ([[steel]]), flyover above eastern approach of the [[San Francisco–Oakland Bay Bridge]]]]

A '''box girder bridge''', or '''box section bridge''', is a [[bridge]] in which the main [[beam (structure)|beams]] comprise [[girder]]s in the shape of a hollow box. The [[box girder]] normally comprises [[prestressed concrete]], [[structural steel]], or a [[composite material|composite]] of steel and [[reinforced concrete]]. The box is typically [[rectangle|rectangular]] or [[trapezoid]]al in [[cross section (geometry)|cross-section]]. Box girder bridges are commonly used for highway [[overpass|flyovers]] and for modern elevated structures of [[light rail]] transport. Although the box girder bridge is normally a form of [[beam bridge]], box girders may also be used on [[cable-stayed bridge|cable-stayed]] and other bridges.