Box girder bridge

Box girder bridge

Underneath the No. 2 Road Bridge in Richmond, British Columbia, Canada
Span range	Medium
Material	Steel, reinforced concrete, prestressed concrete
Movable	Possible
Design effort	High
Falsework required	Yes, 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.