De Ferranti Glossary: "Roman bridge"

Glossary: R

Roman bridge
Roman bridges, built by ancient Romans, were the first large and lasting bridges built. For a list, see Bridges in Rome.

Roman bridges were built with stone and had the arch as its basic structure. Most utilized concrete as well.

Built in 142 BC, the Pons Aemilius, later named Ponte Rotto (broken bridge) is the oldest Roman stone bridge in Rome, Italy.

The biggest Roman bridge was Trajan's bridge over the lower Danube, constructed by Apollodorus of Damascus, which remained for over a millennium the longest bridge to have been built both in terms of overall and span length. They were most of the time at-least 60 ft above the body of water.

An example of temporary military bridge construction are the two Caesar's Rhine bridges

Usual characteristics of Roman Bridges:-
Many are more than 5 meters wide
Most of them slope slightly
Many have rustic work
The stonework has alternating stretcher and header courses; i.e. one layer of rectangular stones is laid lengthwise, and the next layer has the ends facing outwards
Stones linked with dovetail joints or metal bars
Indents in the stones for gripping tools to hold onto