Stone bridges have been used in one form or another for many thousands of years. The earliest surviving stone structures were most likely based on clapper bridges. These are an ancient form of stone bridge formed by large flat slabs of granite or schist supported on stone or resting on the banks of streams.
The oldest surviving record of the use of the more recognizable arch shape as a structural form is the Arkadiko Bridge, dating to the 13th century BC, which is one of four Mycenaean stone corbel arch bridges that form part of a former network of roads, designed to accommodate chariots in Greece. Although this bridge is still in existence and use today it is likely that it developed through empirical rules as well as a process of trial and error.
In the very early years of bridge construction the use of bricks was rare, although brick built bridges with carriageways supported on vaults were constructed in Mesopotania from at least the 6th century BC. However, it was the Romans who were the greatest masonry bridge builders of antiquity. The Romans built arch bridges and aqueducts that could stand in conditions that would have damaged or destroyed the earlier timber designs and their bridges were typified by their semi-circular form and thick piers. These stone arches are immensely strong structures and generally become stronger as they are loaded due to the ability of stone and brick to sustain very large compressive forces. The Romans had a great understanding of forces, geometry and the properties of stone and this allowed them to create spans significantly greater than anything that the world had seen before. The legacy of the Roman bridge builders is encompassed within the six span bridge over the river Tagus at Alcantara in Spain, which contains individual spans of up to 30m.
At about the same time the Chinese were also developing bridges with new geometries (segmental, elliptical, parabolic, etc.) and the Zhaozhou Bridge, built from 595 to 605 AD during the Sui Dynasty in China, is historically significant as it is the world’s oldest open-spandrel, stone, segmental arch bridge. This bridge demonstrates an advanced level of understanding of the forces exerted on the arch, piers and abutments, which was not demonstrated in Europe until the Renaissance period.
After the Romans, stone bridges continued to be built but not in as large a number as before. They were extremely expensive as they required a huge number of skilled labourers and typically took many years to build. Therefore, large stone bridges were more often built under the influence of the Church throughout the middle ages and the Renaissance period. For these bridges no expense was spared in crossing some of the most difficult obstacles, as it was seen as glorifying God in much the same way as the construction of the cathedrals. The Charles Bridge in Prague is a typical example where the bridge itself almost became a site of religious pilgrimage. The legacy of their strength, permanence and durability is the fact that so many outstanding examples from this time survive in seemingly perfect condition to this day.
In terms of volume, the main period of sustained masonry arch building began with the development of the canal systems in the second half of the eighteenth century and continued through the construction of the railway system throughout the nineteenth century. During this period many tens of thousands of masonry arch bridges were built, the vast majority of which remain in service today. However, the completion of the rail networks marked the end of the use of stone and brick in bridge construction with very few having been built since.
