Box girder bridge

Box girder bridge
Underneath the No. 2 Road Bridge in Richmond, British Columbia, Canada
Underneath the No. 2 Road Bridge in Richmond, British Columbia, Canada
AncestorTubular bridge
Relatedjetway, skyway
Descendantsegmental bridge
CarriesPedestrians, automobiles, trucks, light rail, heavy rail
Span rangeMedium
MaterialSteel, reinforced concrete, prestressed concrete
MovablePossible
Design effortHigh
Falsework requiredYes, if cast-in-place reinforced or prestressed concrete is used, which is typical for freeway overpasses
Section of a twin box girder bridge
Erskine Bridge, near Glasgow, Scotland.
Single box girder bridge (concrete), Australia. A similar bridge on this river was fabricated ashore and pushed across its pylons.
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 beams comprise girders in the shape of a hollow box. The box girder normally comprises prestressed concrete, structural steel, or a composite of steel and reinforced concrete. The box is typically rectangular or trapezoidal in cross-section. Box girder bridges are commonly used for highway 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 and other bridges.