The ancient Romans were the first civilization to build large, permanent bridges. Early Roman bridges used techniques introduced by Etruscan immigrants, but the Romans improved those skills, developing and enhancing methods such as arches and keystones. There were three major types of Roman bridge: wooden, pontoon, and stone.
Early Roman bridges were wooden, but by the 2nd century stone was being used. Stone bridges used the arch as their basic structure, and most used concrete, the first use of this material in bridge-building.
Following the conquests of Tarquinius Priscus, Etruscan engineers migrated to Rome, bringing with them their knowledge of bridge-building techniques. The Romans improved on Etruscan architectural techniques. They developed the voussoir, stronger keystones, vaults, and superior arched bridges. Roman arched bridges were capable of withstanding more stress by dispersing forces across bridges. Many Roman bridges had semicircular arches, but a few were segmental, i.e. with an arc of less than 180 degrees.
By the 2nd century BC, the Romans had further refined their bridge-building techniques, using stronger materials such as volcanic ash, lime and gypsum. Also, they began to use iron clamps to hold together bridges, constructing midstream arches, and pentagonal stones to allow for wider vaults.
Between 150 and 50 BCE, many stone Roman bridges were built. Engineers began to use stone instead of wood to exemplify the Pax Romana and to construct longer-lasting bridges. These were the first large-scale bridges ever constructed.
Bridges were constructed by the Roman government to serve the needs of the military and the empire's administration. Sometimes roads and bridges were used for commercial purposes, but this was rare as boats better served the needs of the imperial economy.
By the 2nd century Roman techniques had declined, and they had been mostly lost by the 4th century.
Locations of Roman Bridgess in Roman Britain
- Balmuildy Bridge
- Chesters (Cilurnum) Roman Bridges
- Corbridge (Coriosopitum) Roman Fort and Town
- Hadrian's Wall - Fort - Chesters (Cilurnum)
- Hadrian's Wall - Fort - Newcastle (Pons Aelius)
- Hadrian's Wall - Fort - Stanwix (Uxelodunum)
- Hadrian's Wall - Willowford Bridge Abutment
- Piercebridge (Morbium) Roman Bridge
- Wroxeter (Viroconium Cornoviorum) Roman Fort and City