Arch bridges are structures in which each span forms an arch. The spans range up to about 1,700 feet (518 meters) long. The arch bridge is one of the oldest types of bridges. Early arches consisted of large stone blocks wedged together to form an arch. Today, the majority of arch bridges that have short spans are made of concrete or wood. Arch bridges with long spans are built of concrete or steel.
Engineers must design arch bridges so that the sides of the arch do not spread apart and collapse the bridge. The roadway of some arch bridges lies on top of the arch and is supported by vertical columns called spandrel columns. These columns transfer the load of the roadway to the arch, which bears the weight of the bridge. The roadway of a tied arch bridge is below the curve of the arch. Girders or other types of beams that hang from the arch support the roadway. The girders or beams also connect to the ends of the arch to support the thrust of the bridge.
Examples of this type of bridge are New River Gorge - New River, near Fayetteville, W. Va., Eads - Mississippi River, St. Louis, MO.