Girder Bridges

Girder bridges, which include many highway bridges, are made of beams called girders whose ends simply rest on piers or abutments. These bridges may be used to cross most areas. The span length of girder bridges ranges up to about 1.000 feet (300 meters).

There are two main types of girder bridges. In one type, called a box girder bridge, each girder looks like a long box that lies between the piers or abutments. The top surface of the bridge is the roadway. Box girder bridges are built of steel or concrete. In the other type of girder bridge, the end view of each girder looks like an I or a T. Two or more girders support the roadway. This type of bridge is called a plate girder bridge whenmade of steel, a reinforced or prestressed concrete girder bridge when made of concrete, and a wood girder bridge when made of wood.