Article taken from "The Sunday Sun" 26th November 2000.

 

 

THE STORY THAT SPANS CENTURIES

Millennium Bridge carries on great North tradition

The new 22m Gateshead Millennium Bridge is the talk of the Tyne, but it is just the latest in a series of stunning structures which have helped give the North its worldwide reputation for engineering brilliance.

Experts say the region boasts some of the most fascinating and original constructions in the world.

The 850-tonne blinking eye follows in a rich tradition of innovative designs, such as the much-copies Tyne Bridge in Newcastle and the legendary Transporter Bridge in Middlesbrough.

Professor John Knapton, from the Department of Civil Engineering at Newcastle University, said: "The North is the world’s most important site for historic bridges. This is a result of the fact that our rivers are in deep gorges rather than puny dips – so we tend to get spectacular bridges.

LANDMARK

"It’s also a result of the shipbuilding heritage, which meant the skills in iron and steel fabrication to create the bridges were already here".

Newcastle’s most famous landmark, the Tyne Bridge, served as a model for the much larger Sydney Harbour Bridge.

When it opened over 70 years ago it was the largest single-span bridge in the world.

It was build by Dorman Long of Middlesbrough and was even opened by royalty, in the shape of King GeorgeV.

Knapton said: "The Tyne Bridge is far more elegant than Sydney Harbour Bridge. It has large hinges at each abutment, allowing the whole arch to rotate as the traffic changes the bridge’s shape".

Newcastle’s Swing Bridge is the lowest of the Tyne’s six bridges, and when it opened in 1876 it was the largest of its type in the world.

It was designed by the Tyneside engineer William Armstrong and featured a hydraulically-operated swivel mechanism. This allowed taller, fixed-mast vessels to get far further upstream.

"The Swing Bridge is unique in that it carries its own weight from the north bank to the south bank, while the weight of the traffic is taken to the centre island. It is really two bridges pretending to be one," Knapton explains.

The Middlesbrough Transporter Bridge is one of the only two working bridges of its kind in the world – the other being in Newport, Wales.

EXPENSIVE

It is 850ft (255m) long, 225ft (67.5) high and crosses the River Tees to join Middlesbrough and Port Clarence.

The Professor said: "The Middlesbrough bridge came about as a replacement for a ferry. Usually it would be a stupidly expensive way of replacing a ferry, but both at Middlesbrough and Newport the tides are strong. "This meant that the previous ferry was inconvenient and dangerous".

The current Wearmouth bridge in Sunderland is the third since 1793. It cost 270,000 to build and was opened in 1929 by the then Duke of York.

"The main difference in this bridge is that it is a three-pinned arch, whereas the Tyne Bridge is a two-pinned arch.

"The only reason for the third pin is to make the bridge easier to design. In engineering terms it is statically determinate, whereas the Tyne Bridge is statically indeterminate.

SKILLS

"By the time the Tyne Bridge had been designed, we had the skills to create such structures", said Professor Knapton.

When Newport Bridge, Middlesbrough, was built in 1934 it was the first vertical-lift bridge in the country.

In the late 1980s it became a fixed structure and is now effectively a road bridge.

Prof. Knapton said: "It would cost about 8m to build a bridge like this now, but no one would make a bridge like that."

The Ribblehead Viaduct on the Settle-to-Carlisle railway line was opened in 1876.

It is a quarter of a mile long, 105ft (3.15m) tall and has 24 arches and would have cost around 25,000 to build.

Knapton said: "This is more important because of its setting than because of any engineering features.

"It would cost more to build today mainly because of the high cost of stone masons and bricklayers. To do it all in masonry, as it was built, would cost 60m, but it would probably cost 18m if less labour intensive materials were used."

DESIGNED

The stunning Prebends Bridge in Durham was opened in 1772. It is owned by the Dean and Chapter of Durham Cathedral. The bridge was designed by George Nicholson and was put there to replace a bridge that was washed away in the great floods of 1771.

"This would probably have cost 8000 to build, but today it would cost more like 2.5m."

Valley Bridge in Scarborough, was the principal road artery linking the town centre and the South Cliff. Between 1926 and 1928 the bridge was rebuilt and widened but continued to be used during the work.

The professor added: "Valley Bridge is not particularly innovative, but is a good example of the way in which the Victorians combined art and engineering".