The arch bridge is one of the oldest types of brides and has been in existence in the world since more than 2000 years (Brown 2005). The Romans were the first to take the advantages of the arch in building bridges. There are more than 900 ancient Roman bridges found in Europe; most of them are arch bridges. Applying arch into bridges and buildings has a long history also in the East. The Anji Bridge, the oldest open-spandrel segmental stone arch bridge with a central span of 37 m, was built in AD 605 in Hebei, China (Figure 9.1). The use of cast iron as dovetails to interlock stone segments and open spandrels so as to reduce structural weight and to increase water flow during flooding made it a milestone in the long history of arch bridges. Its survival of at least eight wars, ten major floods, and numerous earthquakes, especially the 7.2-richter-magnitude earthquake in 1966, Xingtai (40 km away from the site) demonstrates the strength and advantage of the arch bridge.