Royal Albert Bridge
Coordinates: 50 ° 24 ′ 28 " N , 4 ° 12 ′ 12" W.
| Royal Albert Bridge | ||
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| use | railroad | |
| Crossing of | Tamar | |
| place | Saltash , UK | |
| Entertained by | Network Rail | |
| construction | Arch bridge , lenticular structure | |
| overall length | 666.8 m | |
| width | 5.13 m ( clear space by the pillars) | |
| Number of openings | 19th | |
| Longest span | 138.7 m | |
| Construction height | 22 m | |
| Clear height | 30.5 m | |
| start of building | May 1854 | |
| completion | April 1859 | |
| opening | May 4, 1859 | |
| planner | IKBrunel | |
| location | ||
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The Royal Albert Bridge is a railway bridge over the Tamar in the United Kingdom between Plymouth in Devon and Saltash in Cornwall . The construction of the river bridge is unique: it consists of two 138.7 m long wrought iron lenticular truss girders 30.5 m above the water, which stand out with their upper chords made of mighty, curved pipes. The approach bridges are designed as conventional solid wall girders . The total length of the bridge is 666.8 m.
It was designed by Isambard Kingdom Brunel . Surveying and investigation of the river bed began in 1848, construction began in 1854. The first field of the river bridge was moved to its position in 1857 and the completed bridge was opened on May 2, 1859 by Prince Albert . Brunel died that same year, and his name was placed in memory at both ends of the bridge over the portals. In the twentieth century the approach bridges were replaced and the river bridges reinforced. This bridge has attracted tourists since it was built, and it is featured in many paintings, photographs, and travel guides. There were anniversary celebrations in 1959 and 2009.
Cornwall Railway
In the 1830s two competing projects were proposed for a railway line to Falmouth in Cornwall. The 'central' project was a stretch from Exeter around north Dartmoor , an easy-to-build stretch but which would attract little local traffic between its endpoints. The other, 'close to the coast' project was a route with many technical difficulties but was able to connect the important port city of Plymouth and the industrial district at St Austell . The central project was proposed by the London and South Western Railway , while the offshore project was proposed by the Cornwall Railway and supported by the Great Western Railway , which wanted a connection to the South Devon Railway at Devonport . In 1845, the Cornwall Railway moved for a parliamentary resolution to build the line. The request was rejected, however, in part because William Moorsom wanted to transport the trains across the Hamoaze on the ferry to Torpoint . Isambard Kingdom Brunel then took over the role of chief engineer and suggested crossing the water a little higher upstream at Saltash. Parliament passed a resolution approving this plan on August 3, 1846.
draft
This bridge was the third in a series of three large wrought iron bridges built in Britain in the mid-19th century. It was influenced by the two previous ones , both designed by Robert Stephenson . The two central openings of Brunel's bridge are novel modifications of the construction that Stephenson used in 1849 for the High Level Bridge over the Tyne in Newcastle . In the same year Brunel visited the construction site of Stephenson's Britannia Bridge over Menai Street .
From 1849 to 1853 Brunel built his own iron bridge. The Chepstow Railway Bridge carried the South Wales Railway over the Wye and consisted of a 91 m long river bridge with a tubular main girder curved slightly upwards and a foreshore bridge with three fields of 30 m each, which were designed as conventional solid girders. This is a very similar solution to that used later for the bridge over the Tamar.
At Saltash the river is approximately 340 m wide. Brunel's first thought was to cross it on a wooden viaduct with a central opening of 78 m and six side openings of 32 m each at a clearance height of 24 m above the water. However, this was rejected by the Admiralty, which had legal jurisdiction over all navigable waters. Therefore Brunel created a second draft for a clearance height of 30 m with two fields of 91 m and two fields of 61 m length.
The final and executed design provides for two main openings of 138.7 m with a clearance height of 30.5 m above the mean spring flood . These two fields are designed as lens carriers. Lens carriers made of iron profiles were already used by Georg Ludwig Friedrich Laves, a friend of Brunel, in Hanover and used by Friedrich August von Pauli for the first Großhesseloher bridge in Munich. Brunel's design, however, is unique in that he uses a mighty, curved wrought iron tube for the pressurized upper chord, while the lower chord is made up of a pair of chains rather than girders. Each of these beams is externally statically determined and therefore does not exert any horizontal force on the pillars, which is extremely important as the bridge runs to the right and left of the main openings in the arch. Between these two straps there is an association of diagonal and vertical struts. The latter are extended as a hanger under the lower chord up to the roadway girder, which is designed as a continuous solid wall girder.
The approach bridges consist of a total of 17 much shorter fields that are spanned by normal solid wall girders. On the Cornish bank there are ten lengths (viewed from Saltash train station in the direction of the river) 20.6 m - 21.2 m - 21.2 m - 21.2 m - 21.2 m - 21.2 m - 22, 1m - 23.8m - 25.5m - 28.3m. On the banks of Devon there are seven with lengths (from the river towards St. Budeaux) 28.3m - 25.5m - 23.8m - 22.1m - 21.2m - 21.2m - 21 , 2 m. This results in a total length for all 19 fields of 666.8 m.
construction
The first task was a thorough survey of the river bed. On April 26, 1848, an iron cylinder 1.8 m in diameter and 26 m in height was launched in the tamar. The river bed could be examined from its bottom in order to determine its condition and locations with stable subsoil. At the time, the Cornwall Railway was struggling to raise funds and most of the work was stopped that summer, but Brunel was given a small budget to continue investigating. The cylinder was lowered in 35 different locations and a total of 175 holes were drilled.
In 1853, the Cornwall Railway's board of directors examined offers to build the bridge and it was decided to transfer the work to Charles Mare. This shipbuilder from Blackwall (London) had already done the ironwork for the Britannia Bridge. He asked for £ 162,000 for the bridge at Saltash, but had to file for bankruptcy on September 21, 1855. Brunel suggested that the railway company carry out the work on the bridge itself and not engage any other contractor, which the company approved.
Mares' first assignment was to set up a construction site on the east bank with a quay and workshops. Next he had an iron cylinder 11.3 m in diameter and 27.4 m high made as a work space for the construction of the central pillar. This was launched in May 1854 and moored in the middle of the river between four pontoons. Its bottom was shaped in such a way that it conformed to the shape of the rocky subsoil measured in 1848. After being set down on the river bed, it was pumped dry. The mud inside was removed and a solid pillar was built up above the water level. This work was finished in November 1856.
The piers of the approach bridge on the Cornish side of the river were completed in 1854, after which the girders for these fields were pulled up to their place of installation. The next step was to build the main girder for the western opening of the river bridge. The chain links for the lower chord are 6.1 m long. Many of these came from the temporarily suspended work on Brunel's Clifton Suspension Bridge , others were re-rolled for Saltash. The first girder of the river bridge was swum in on September 1, 1857 and raised to its final height in stages of 90 cm each while the piers were built under it. The central pillar consists of two cast-iron octagonal pillars, the land-side pillar of ordinary masonry.
After the first main girder had left the building site, construction of the second main girder could begin. This was floated into its place of installation on July 10, 1858 and raised like the first carrier. It reached its final position on December 28th, 1858. After the second girder had been completed, part of the building site was cleared to enable the construction of the last landside pillar. Now the superstructures of the foreland bridge on the Devonian side could also be raised. The work was sufficiently advanced that the directors were able to conduct a train inspection on April 11, 1859.
Before the first main girder was launched, it had been tested. For this purpose, both ends were stored on sturdy piles of wood and the remaining scaffolding removed. Static loads of 4.2 and 7.5 t / m were applied to the deck and the deflection was measured. The remaining deflection after removing the loads was also measured. After completion of the bridge, William Yolland carried out the statutory acceptance inspection on April 20, 1859 on behalf of the Board of Trade . He let a heavy train drive over the bridge and measured deflections of 29 mm in the east and 30 mm in the west main girder. Overall, he called the result “extremely satisfactory”.
opening
As early as 1853, Prince Albert agreed that the bridge would be named after him. He was therefore invited to hold the opening ceremony, and so he traveled on a special train from Windsor on May 2, 1859 . Several thousand spectators attended that day, but Brunel was absent due to illness. Invited guests from Cornwall did not arrive in time for the celebration as their train in Liskeard was damaged. Public transport began on May 4, 1859.
Changes since 1859
The words IK BRUNEL, ENGINEER, 1859 appear in large metal letters at either end of the bridge. They were installed as a memorial to Brunel after his death on September 15, 1859. In 1921, the bridge received new platforms for access to its top, which covered part of the lettering, but in 2006 (on Brunel's bicentenary), Network Rail moved the platforms to the inside of the pillars so that the writing can be clearly seen again. The platforms were temporarily removed as early as 1959 and the bridge was floodlit on the occasion of its centenary.
In 1905, 401 new cross members were installed to take account of the increased weight of the locomotive. In 1908, the first two fields of the bridge just behind Saltash train station were replaced by wider ones so that the exit points could be moved onto the bridge. The remaining fields of the approach bridges on both sides of the river were replaced in 1928 and 1929. In the 1930s, new cross braces and diagonal loop connectors were installed between the vertical bars to further strengthen the bridge and keep the chains in the correct position.
Individual evidence
- ^ Edward Ostler: History of the Cornwall Railway 1835-1846 . Avon-Anglia, Weston-super-Mare 1982, ISBN 0-90546-648-9 .
- ^ Charles Matthew Norrie: Bridging the Years - a short history of British Civil Engineering . Edward Arnold (Publishers) Ltd, 1956.
- ↑ a b c d e f John Binding: Brunel's Royal Albert Bridge . Twelveheads Press, Truro 1997, ISBN 0-90629-439-8 .
- ^ A b E T MacDermot: History of the Great Western Railway, volume II 1863-1921 . Great Western Railway , London 1931.
- ^ Alan Bennett: The Great Western Railway in East Cornwall . Runpast Publishing, Cheltenham 1990, ISBN 1-870754-11-5 .
- ↑ Illustrated Railway Supplement . In: West Briton & Cornwall Advertiser . No. 2547, 1859.
- ^ Brunel's Royal Albert Bridge unveiled in all its splendor . Network Rail. Archived from the original on September 29, 2011. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved March 23, 2010.
Web links
- Royal Albert Bridge. In: Structurae
- Brunel's Royal Albert Bridge, the Tamar river crossing (English; PDF; 553 kB)
- Royal Albert Bridge
- William Humber: A Complete Treatise on Cast and Wrought Iron Bridge Construction ; Description of the Royal Albert Bridge , pp. 248-251. Lockwood & Co., London 1870. Digitized on Google Books
- Viaduc de Saltash . Plan sketches. In: Mémoires de la Société des Ingénieurs Civils. Paris 1855, ( digitized on le Cnum - Conservatoire numérique des Arts et Métiers )