History of concrete bridges

No-one knows how the bridge concept really began but early man would have used fallen trees, stepping stones and other naturally occurring materials to cross geographical barriers.

Some of the earliest surviving bridges date from around the second Century BC. Typically, they were stone arches, a form that dominated bridge construction until the arrival of wrought iron and steel in the early 18th Century and, 150 years later, concrete. Most bridges were built by the church and two Renaissance stone bridges can still be seen in Paris - the Pont Notre Dame (1305) and the Pont Neuf (1606).

It was in the 18th Century that bridge design began to develop into a science, led by an engineering school founded in Paris. Its director, Jean Perronet, perfected the masonry arch, with its low sweeping curve and slender piers. Soon afterwards, attention switched to England where the invention of the steam locomotive called for stronger bridges. In 1794, iron was first used for the chain cables of a suspension bridge over the River Tees and 1779 saw the first all-iron bridge over the Severn at Coalbrookdale. This arch bridge, spanning 100ft, is still in service.

Just when the masonry arch bridge was reaching its peak around the beginning of the 20th Century, reinforced concrete arrived on the scene. Since then, it has become the major construction material for bridges as it has for most structural and civil engineering applications, with its intrinsic versatility, design flexibility and, above all, natural durability.

Although several British engineers had been using concrete early in the 19th Century, its use in British bridges did not develop until the latter half of the 20th Century. It is estimated that at least 75% of the Highways Agency concrete bridge stock has been built since 1960.

In contrast, concrete arches were being buit in continental Europe as far back as the 1850s by Gariel, Coignet and then Monier.

The earliest known example of a mass concrete bridge in the UK, using lime concrete, was on the District Line, near Cromwell Road, West London, designed by Thomas Marr Johnson for Sir John Fowler and built c.1865. Other British engineers began to use plain concrete for bridge superstructures, notably Philip Brannan, who erected a three-span concrete arch, including a 50ft middle span, at Seaton in Devon in 1877.

Railway engineers were also active at this time, using plain concrete on the Dochart Viaduct, with the London and South Western Railway and the West Highland Railway using mass concrete towards the end of the century. Plain concrete was used on the Carrington Viaduct (1903) and the first British reinforced concrete rail bridge, which had a 28 ft (8.5 m) span, was built in Dundee in 1903. This was followed by reinforced concrete bridges designed by Mouchel (Bristol 1907) and Coignet (Bargoed, Wales). By the 1930's there was a significant increase in the use of reinforced concrete.

The use of reinforced concrete probably started with the Homersfield Bridge over the River Waveney on the Norfolk/Suffolk border in 1870, when iron was embedded in concrete, but it was not until the first decade of the 20th Century that reinforcement, as we know it today, was introduced. This was due almost entirely to L.G. Mouchel, the UK agents for the Hennebique system. The first project in the UK was an 18ft span bridge at Chewton Glen in Hampshire in 1902, followed two years later by a 40ft span beam and slab bridge at Sutton Drain in Hull.

Runneymede Bridge, Surrey. Balanced cantilever construction designed by Ove Arup, 1980

Other systems followed including Monier (Copnor footbridge, 1902); Kahn (Lucker, Northumberland, 1906); Considere (Great Eastern Railway, Tottenham, 1908) and Coignet (Metropolitan Railway, Kings Cross). These pioneers created the platform for local authority designs, notably in Somerset and Devon.

By 1930 there were about 2000 reinforced concrete bridges in UK and notable designers such as Sir Owen Williams emerged between the two World Wars e.g. Montrose (1930). Other major bridges of this period were the Royal Tweed Bridge, Berwick (Mouchel); Chiswick and Twickenham River Thames Bridges (Considere); King George V Bridge, Glasgow and, possibly the best of the period, Waterloo Bridge, London (RPT, 1938-42).

It is uncertain when precast concrete was introduced but early applications revolved around railway footbridges, with Southern Region leading the way at Oxshott, Surrey (1908) and Exeter (1923). An outstanding precast structure of the time was at Mizen Head, Cork (1908), an arch with a 172ft span.

The outstanding feature of concrete bridges both during and after the Second World War was the advent of prestressed concrete, used to rebuild the many bridges that had been destroyed, especially on the Continent.

By 1950, bridges by Freyssinet and Magnel had been built, using precast segments joined by concrete or mortar; Finsterwalder had constructed the first in-situ box girder bridge using cantilever construction and in the 1960s, the first incrementally launched bridge was built in Germany.

In the UK, a stock of emergency prestressed concrete beams was held during the War and used afterwards in permanent bridgeworks. They were designed by Dr. Mautner of the Prestressed Concrete Company, a subsidiary of Mouchel licensed by Freyssinet. This partnership was responsible for Nunn's Bridge, Fishtoft near Boston (1948), the first in-situ prestressed concrete road bridge. Other early examples were the Adam Viaduct near Wigan (1943) and the Rhinefield Bridge in Hampshire. The main prestressing systems in use at this time were Freyssinet, Hoyer and Lee-McCall.

The first major prestressed concrete road bridge was the replacement for Northam Bridge, Southampton (1954). Larger and larger bridges were built using prestressed concrete including Cavendish (1956), Clifton, Nottingham (1958) and Bridstow, near Ross-on-Wye (1960), all cantilevered, suspended span bridges using precast beams.

Reinforced concrete was still being used in the 1950s for larger bridges, especially arches, notably Lune Bridge carrying the M6, but by the end of the 1960s, prestressed concrete had largely superseded reinforced concrete with box girders being the dominant structural form.

Expansion of the motorway network demanded large numbers of concrete bridges, a functional and cost-effective solution to society's needs. The main emphasis on bridge design became economy and durability rather than style. This inspired any number of developments and construction techniques, mainly involving precast segmental construction (Hammersmith Flyover, 1961); resin joints (Rawcliffe, Yorkshire 1968); match casting (Byker, Newcastle 1979); incrementally launched bridges, the first example in UK being the Shepherds House Rail Bridge near Reading in 1977; cable-stayed, typified by Lyne Bridge in Surrey, one of the first examples in the world.

The durability of concrete has also been recognised by its significant use on major estuarial crossings such as the Humber, Medway and Severn.

Design and construction techniques continue to evolve to satisfy the increasing demands of the UK transport network e.g. integral bridges.