Arch bridge refers to a bridge which is made in the shape of a curved arch and has abutments at each end of the bridge. Such a bridge is sustained by the mechanism of transferring the weight of the bridge (and its loads) on a horizontal thrust which is restrained by the abutments.
There are different designs and mechanism used by the various architects in the construction of the arch bridges. There are some examples of arch bridges where they are made of a single continuous arch without any breaks.
There are also examples where the bridge is made from a series of arches instead of a single one.
The concept of arch bridges has been around for a very long time. One of the current arch bridges, which is also the oldest dates back to September 30, 1916. The bridge being referred to is the Hell Gate Bridge which is about 5.2 km long and is situated in New York City, USA.
The second oldest bridge is the Bayonne Bridge (1762m long) situated in Kill Van Kull, USA. Other oldest arch bridges include the Sydney Harbour Bridge in Australia (1149m long), the Birchenough Bridge in Zimbabwe (378.2m) and the Henry Hudson Bridge in New York City, USA (673m long)