It is exciting to know that there are some early iron and steel bridges still in use today. The world’s first cast iron bridge was built at Coalbrookdale, Telford, England, in 1779 and is still in use today carrying occasional light transport and pedestrians.
Until 1840 the construction material used was either cast iron or wrought iron or a combination of both. In the early 1800s cast iron was beginning to be replaced by wrought iron and many of the early railway bridges were built of riveted wrought iron construction.
It was not until the late 1800s that steel began to replace wrought iron and by the early 1900s wrought iron was no longer available, as worldwide, steel makers had moved to producing carbon steel, a much more reliable material.
|1857||Weichsel Bridge, Dirscham, East Prussia was the first large wrought iron girder railway bridge to be built in Germany.|
|1863||Menangle Viaduct, New South Wales, Australia is the oldest existing railway bridge in Australia. It has two wrought iron riveted box girders and originally had three equal spans of 49.4m. However, these spans have now been halved by the addition of intermediate piers to allow the bridge to accommodate heavier loading.|
|1870||Kymijoki railway bridge, Koria, Finland, was the first 3-span steel truss bridge built in Finland. Originally for a railway, this riveted bridge was converted to carry road traffic in 1923, and is still in use today as a footbridge.|
|1883||Brooklyn Bridge, USA, was the first steel wire and steel bridge to be built in the world.|
|1884||Garabit Viaduct, St.Flour, France, built by Gustav Eiffel is one of the first wrought iron truss arch bridges to be built in the world.|
|1888||Tenryugawa Bridge – First railway bridge built in Japan using steel.|
|1890||First major steel cantilever railway bridge in the world, over the Forth near Edinburgh, Scotland.|
|1897||Eitaibashi Bridges – First steel highway bridge built in Japan, used 690Mpa steel developed for navy vessels.|
Most of these structures are still in use today.
In the mid 1900s the use of welding brought major changes to the steel fabrication industry. In some countries however it took until the 1960s before rivets became obsolete and bolted and welded construction took over.
From the 1930s many of the large structures being built were of steel. Notable examples include:
- 1931 – George Washington Suspension Bridge, USA.
- 1932 – Sydney Harbour Bridge, Australia.
- 1936 – Hangang Bridge, Seoul, Korea – Tied-arch with 6 spans of 63.5m (totaling 381m).
- 1937 – Golden Gate suspension bridge, San Francisco, USA.
From the 1950s steel has become more competitive for highway bridges in the medium span range 45m – 100m. Today the competitiveness of steel is being realised over all span ranges, as steel makers and fabricators work closely together. The introduction of new high strength steels, modern fabrication workshops (with automatic welding girder lines), and the availability of very large cranes for handling and erection are some of the reasons why steel is so competitive.
Ashley G. // Editor SMC