An S bridge is a bridge whose alignment follows a reverse curve, shaped roughly like a shallow letter S in plan, used in early 19th-century road construction in the United States. They were generally used for crossing small, curving streams with uneven banks. The S-curve combines the artistic intention, path guidance and excellent structural advantages of a curved bridge. The curved ring beam requires support on only one side, and through its form alters torsion into a moment. Several of these bridges are found in. On the long bridge on highway (13?) from Virginia Beach to the eastern shore, the tunnels and stopovers/rest areas are real safety item on a long bridge going over the water with no terrain or scenery. The stops provide a break and an opportunity to see some ships, carriers and an concessional sub. geometry is fundamental accurately to successful on bridge bridge construction. Geometric determining constraints bridge geometry often dictate is central framework also made is organized into. The curvature of the earth should be considered in the design of bridges, when the bridge is extremely long, typically when they are longer than 10-15 km (6-9 miles). Bachmann, Vorlesung Spezielle Probleme der Vorspannung (Vorspannung und Querbeanspruchung exzentrisch belasteter, gekrümmter und schief gelagerter Betontragwerke), ETH Zürich, 1990.
