Bridges are among the most important， and often the most spectacular， of all civil engineering There are six main types of bridges: beam bridges， cantilever bridges， arch bridges， suspension bridges， cable-stayed bridges and truss A bridge is designed for trains， pedestrian or road traffic， a pipeline or waterway for water transport or barge An aqueduct is a bridge that carries water， resembling a viaduct， which is a bridge that connects points of equal A road-rail bridge carries both road and rail Bridges may be classified by how the forces of tension， compression， bending， torsion and shear are distributed through their Most bridges will employ all of the principal forces to some degree， but only a few will The separation of forces may be quite In a suspension or cable-stayed span， the elements in tension are distinct in shape and In other cases the forces may be distributed among a large number of members， as in a truss， or not clearly discernible to a casual observer as in a box Bridges can also be classified by their lineage， which is shown as the vertical axis on the diagram to the
