FACTS AND FIGURES – The Tamar Bridge

by Old Plymouth Society

Published March 2012

Although not built for over a hundred years after Royal Albert Bridge, it would be hard to ignore the Tamar Bridge. It spelt the demise of the 900 year old ferry link, which had plied its way across the Tamar from the days of row boat to chain ferry.

This bridge will celebrate its 50th anniversary this year, having been opened to pedestrians on Tuesday 24 October 1961. It was officially opened by the Queen Mother in April 1962. It was built without a Government grant, having been a joint venture by Cornwall County Council and Plymouth City Council. In 1956 the 2 councils promoted a parliamentary bill to compulsory purchase land to build the bridge, paying back the cost of its construction by way of tolls. Royal Assent was granted in 1957 at the time of the first Tamar Bridge Act. It is governed by Tamar Bridge and Torpoint Ferries Joint Committee which is made up of 5 councillors from Plymouth and 5 from Cornwall. 

It was designed by Construction Engineers Mott, Hay & Anderson. It was built in only 2 years by the Cleveland Bridge & Engineering Company and cost 1.3million. When it opened it was the longest span bridge in England, as well as being the first major suspension bridge to be constructed after WW2. Its concrete deck was capable of carrying lorries up to 38 tonnes. 4000 vehicles a day passed over it, today 50000 vehicles do!

In the late 1990s it was discovered that the bridge would not meet the standards laid down by a new European Union directive. This stated that bridges should be capable of carrying lorries up to 40 tonnes. The concrete deck of the bridge had deteriorated so much that it was in danger of having the weight of the lorries reduced to 17 tonnes.

At a cost of 35million, work on widening and strengthening it began in March 1999. The principle designers were Hyder Consulting Ltd, and the work was carried out by the same contractors who built the original bridge. It holds the record as having remained open throughout this work. The additional lane and walkway/cycle lane were dubbed Nippon clip ons, as the technique of clipping on the cantilever platforms had been used in Japan. Originally these platforms were only going to be temporary, in order that the strengthening work on the main deck could be carried out without closing the bridge, but it was decided to leave them in place thus forming a 5 lane bridge.

The work was completed in December 2001 and involved the following:
The concrete deck was replaced with an orthotropic steel deck. This was made up of steel plates supported underneath by ribs or stiffeners. Each of the 82 steel panels weighs 20 tonnes and measures approximately 49 feet by 20 feet. They were made in Darlington, transported by lorry and welded together on site.
18 new diagonal cable stays were fitted
The strengthening and widening project was recognised by several leading bodies in this field and it won prestigious awards.
The total weight of the bridge at the end of the refurbishment was 25 tonnes more than the original bridge.
Princess Ann officially opened it on April 26 2002  40 years after the Queen Mother had opened the original bridge.
In 2007 16 million vehicles crossed over the bridge. Interestingly, this bridge vibrates when a train crosses Royal Albert Bridge!
An electronic Tag system of collecting tolls was introduced in January 2007. 

There is a plaque at the Bridge Office building on the Plymouth side which quotes some interesting figures:
Main span: 1100 feet
Side spans: 374 feet 
Length over abutments: 2107 feet 6 inches
Height of towers: 240 feet above piers
Piers: On 30 feet diameter caissons founded on rock below the river bed
Cables: Each consists of 31 steel wire ropes 2 and three eighths inches in diameter
Anchorages are in 50 feet tunnels. Each take 3800 tons pull.
Weight of suspended structure: 8000 tons.

There is to be an event on the Saltash Waterfront on Sunday 23 October to celebrate nine centuries of ferry crossings that ended on October 23 1961, which will include ferry trips following the old route and an exhibition of historical photographs. There is to be an event to celebrate the 50th birthday of the Tamar Bridge, the final details are being arranged as you read this!

On the subject of bridges, the following is a list of fast facts regarding the refurbishment of Royal Albert Bridge which is part of the 10 million current Network Rail programme and work on the bridge will take around 2 years to complete.
12 different coats of old paint dating back to 1859 will be removed.
1000 tonnes of grit blast abrasive will be extracted. 
35000litres of special paint will be applied in 4 coats.
1800 individual steelwork repairs will be carried out.
50,000 new bolts and over 100 tonnes of new steel will be installed.
2 million hours will be invested in the work.

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