A box girder bridge is a bridge in which the beams are made up
of box shaped girders. The box girders consist of concrete,
steel or a combination of both. Most of the modern elevated
structures are built on the basis of the box girder bridge. Most
of us have travel on the box girder bridges regularly. The most
common examples are the flyovers and the structures built for
light rail transport. They can sustain heavy weight and hence
used in the construction of flyovers. These are used to
construct crossways for pedestrians. Box girders are used on
cable styled bridges and other forms but generally they are a
form of Beam Bridges. The support beams of the girders are
tightly coupled together to form a hollow box. This hollow box
can have the shape of a rectangle, tightly coupled triangles or
trapezium. The box girder bridges offer a stronger support for
bridges constructed with an arch. The most famous Bay Bridge in
California, connecting San Francisco and Oakland is a classic
example of the Box girder bridge.