Clyde Tunnel
Encyclopedia
The Clyde Tunnel is a crossing beneath the River Clyde
in Glasgow
, Scotland
. Two parallel tunnel
tubes connect the districts of Whiteinch
to the north and Govan
to the south in the west of the city.
were hit by the problem of crossing the Clyde. Downstream of Jamaica Street in the city centre
, it was perceived to be impossible to build a bridge
due to the prevalence of shipping
in what had been the second city of the British Empire
still reliant on the sea. The solution — to build a tunnel beneath the river — was not a new one, with the Harbour Tunnel at Finnieston
having been built in the 1890s. However, the Clyde Tunnel project was to be built in the boom of the car era and would be a much larger project. It was given the green light in 1948 but financial difficulties prevented work from beginning until 1957.
, based on Marc Isambard Brunel
's design used for the Thames Tunnel
a century earlier, was used to dig the two tunnelshttp://www.glasgow.gov.uk/en/Residents/GettingAround/Roads/ClydeTunnel. The tunnels were cut perfectly circular with the road deck sitting a third of the way uphttp://www.holdyourbreath.org/facts/galleryone.html. Under each road deck is the pedestrian/cycle tunnel and ventilation ducts. 16 miners
operated the shield working shifts in a compressed air
environment to ensure that the rock and the river above did not collapse into the tunneling area. The digging itself would be done only with great difficulty due to the geology
of the area, hard rock sitting under a soft silt
layer beneath the river.
The techniques for decompression after a period of working in a high pressure atmosphere had not been perfected at this time and – also owing to the prevalence of workers refusing to go through the decompression sequence given the length of time required (around an hour) – there were a number of cases of decompression sickness
diagnosed as a result, resulting in two fatalities. Also, work on the tunnel was halted for a time after an explosion when compressed air escaped through the tunnel lining into the river, flushing outward in a fountain.
The first completed tunnel tube, for northbound traffic, was eventually opened by Queen Elizabeth II
on 3 July 1963, with the southbound tunnel opening in March 1964. The total cost of the project was £
10 million. Ironically, by this point, the migration of port facilities downstream to the deeper waters of the Firth of Clyde
and improvements in engineering
technology had allowed the consideration of bridges downstream of the city centre, namely the Kingston Bridge
and, much further downstream than the Tunnel, the Erskine Bridge
.
approaching 6% or 1:16. The width of the river at this point is 123 m. Each road tunnel carries two lanes of traffic as part of the A739 road, and are completely separate except for a very small crossover passage between the road tunnels at the nadir
(barely large enough for a single pedestrian). They are monitored and controlled from the two Portal towers, one at each end of the tunnel, where CCTV
monitors the entirety of the tunnel. Beneath the tunnel decks run foot and cycle tunnels, and below those the tunnels' services.
The latest set of repairs, costing as much as the initial outlay for construction, is for a second modern fireproof layer to allow the tunnel to meet European safety standards after St Gotthard and Mont Blanc tunnel fires, along with new air extraction systems and new lighting
. For these works, which began in March 2005 and were scheduled to last until at least April 2006, one of the tunnels remains closed during off-peak hours (19:00 to 07:00 daily). This work, however has been beset with problems, and as of August 2007 is still to be completed.
Signs informing road users of the temporary tunnel bore closures have had the completion date blanked out. The roadworks are coinciding with the Hold Your Breath project aiming to add an art
istic experience to travel through the tunnel. The pedestrian tunnel is also having its years of graffiti
removed as part of its beautification project, however it is an on-going problem, and often is replaced within weeks of being removed.
video Gobstopper, for which he won the Beck's Futures
art prize in 2000.
The Western tunnel was closed in September 2009, apparently so it can also have security gates fitted.
River Clyde
The River Clyde is a major river in Scotland. It is the ninth longest river in the United Kingdom, and the third longest in Scotland. Flowing through the major city of Glasgow, it was an important river for shipbuilding and trade in the British Empire....
in Glasgow
Glasgow
Glasgow is the largest city in Scotland and third most populous in the United Kingdom. The city is situated on the River Clyde in the country's west central lowlands...
, Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
. Two parallel tunnel
Tunnel
A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...
tubes connect the districts of Whiteinch
Whiteinch
Whiteinch is a district in the Scottish city of Glasgow. It is situated north of the River Clyde between the Partick and Scotstoun areas of the city...
to the north and Govan
Govan
Govan is a district and former burgh now part of southwest City of Glasgow, Scotland. It is situated west of Glasgow city centre, on the south bank of the River Clyde, opposite the mouth of the River Kelvin and the district of Partick....
to the south in the west of the city.
History
Efforts to improve the transport infrastructure of Glasgow post-World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
were hit by the problem of crossing the Clyde. Downstream of Jamaica Street in the city centre
Central business district
A central business district is the commercial and often geographic heart of a city. In North America this part of a city is commonly referred to as "downtown" or "city center"...
, it was perceived to be impossible to build a bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...
due to the prevalence of shipping
Shipping
Shipping has multiple meanings. It can be a physical process of transporting commodities and merchandise goods and cargo, by land, air, and sea. It also can describe the movement of objects by ship.Land or "ground" shipping can be by train or by truck...
in what had been the second city of the British Empire
British Empire
The British Empire comprised the dominions, colonies, protectorates, mandates and other territories ruled or administered by the United Kingdom. It originated with the overseas colonies and trading posts established by England in the late 16th and early 17th centuries. At its height, it was the...
still reliant on the sea. The solution — to build a tunnel beneath the river — was not a new one, with the Harbour Tunnel at Finnieston
Finnieston
Finnieston is an area of Glasgow, Scotland, situated on the North bank of the River Clyde and between the city's West End and the city centre. It is home to the SECC, where many musical concerts and important conferences are held...
having been built in the 1890s. However, the Clyde Tunnel project was to be built in the boom of the car era and would be a much larger project. It was given the green light in 1948 but financial difficulties prevented work from beginning until 1957.
Construction
A tunnelling shieldTunnelling shield
A tunnelling shield is a protective structure used in the excavation of tunnels through soil that is too soft or fluid to remain stable during the time it takes to line the tunnel with a support structure of concrete, cast iron or steel...
, based on Marc Isambard Brunel
Marc Isambard Brunel
Sir Marc Isambard Brunel, FRS FRSE was a French-born engineer who settled in England. He preferred the name Isambard, but is generally known to history as Marc to avoid confusion with his more famous son Isambard Kingdom Brunel...
's design used for the Thames Tunnel
Thames Tunnel
The Thames Tunnel is an underwater tunnel, built beneath the River Thames in London, United Kingdom, connecting Rotherhithe and Wapping. It measures 35 feet wide by 20 feet high and is 1,300 feet long, running at a depth of 75 feet below the river's surface...
a century earlier, was used to dig the two tunnelshttp://www.glasgow.gov.uk/en/Residents/GettingAround/Roads/ClydeTunnel. The tunnels were cut perfectly circular with the road deck sitting a third of the way uphttp://www.holdyourbreath.org/facts/galleryone.html. Under each road deck is the pedestrian/cycle tunnel and ventilation ducts. 16 miners
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
operated the shield working shifts in a compressed air
Compressed air
Compressed air is air which is kept under a certain pressure, usually greater than that of the atmosphere. In Europe, 10 percent of all electricity used by industry is used to produce compressed air, amounting to 80 terawatt hours consumption per year....
environment to ensure that the rock and the river above did not collapse into the tunneling area. The digging itself would be done only with great difficulty due to the geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
of the area, hard rock sitting under a soft silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
layer beneath the river.
The techniques for decompression after a period of working in a high pressure atmosphere had not been perfected at this time and – also owing to the prevalence of workers refusing to go through the decompression sequence given the length of time required (around an hour) – there were a number of cases of decompression sickness
Decompression sickness
Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...
diagnosed as a result, resulting in two fatalities. Also, work on the tunnel was halted for a time after an explosion when compressed air escaped through the tunnel lining into the river, flushing outward in a fountain.
The first completed tunnel tube, for northbound traffic, was eventually opened by Queen Elizabeth II
Elizabeth II of the United Kingdom
Elizabeth II is the constitutional monarch of 16 sovereign states known as the Commonwealth realms: the United Kingdom, Canada, Australia, New Zealand, Jamaica, Barbados, the Bahamas, Grenada, Papua New Guinea, the Solomon Islands, Tuvalu, Saint Lucia, Saint Vincent and the Grenadines, Belize,...
on 3 July 1963, with the southbound tunnel opening in March 1964. The total cost of the project was £
Pound sterling
The pound sterling , commonly called the pound, is the official currency of the United Kingdom, its Crown Dependencies and the British Overseas Territories of South Georgia and the South Sandwich Islands, British Antarctic Territory and Tristan da Cunha. It is subdivided into 100 pence...
10 million. Ironically, by this point, the migration of port facilities downstream to the deeper waters of the Firth of Clyde
Firth of Clyde
The Firth of Clyde forms a large area of coastal water, sheltered from the Atlantic Ocean by the Kintyre peninsula which encloses the outer firth in Argyll and Ayrshire, Scotland. The Kilbrannan Sound is a large arm of the Firth of Clyde, separating the Kintyre Peninsula from the Isle of Arran.At...
and improvements in engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
technology had allowed the consideration of bridges downstream of the city centre, namely the Kingston Bridge
Kingston Bridge, Glasgow
The Kingston Bridge is a balanced cantilever dual-span ten lane road bridge made of triple-cell segmented prestressed concrete box girders crossing the River Clyde in Glasgow, Scotland. The largest urban bridge in the United Kingdom, it carries the M8 motorway through the city centre...
and, much further downstream than the Tunnel, the Erskine Bridge
Erskine Bridge
The Erskine Bridge is a cable-stayed box girder bridge spanning the River Clyde in west central Scotland, connecting West Dunbartonshire with Renfrewshire....
.
The tunnels
The tunnels are each 762 metres (2,500 feet) long with a gradientGradient
In vector calculus, the gradient of a scalar field is a vector field that points in the direction of the greatest rate of increase of the scalar field, and whose magnitude is the greatest rate of change....
approaching 6% or 1:16. The width of the river at this point is 123 m. Each road tunnel carries two lanes of traffic as part of the A739 road, and are completely separate except for a very small crossover passage between the road tunnels at the nadir
Nadir
The nadir is the direction pointing directly below a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface there. Since the concept of being below is itself somewhat vague, scientists define the nadir in more rigorous...
(barely large enough for a single pedestrian). They are monitored and controlled from the two Portal towers, one at each end of the tunnel, where CCTV
Closed-circuit television
Closed-circuit television is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors....
monitors the entirety of the tunnel. Beneath the tunnel decks run foot and cycle tunnels, and below those the tunnels' services.
Repair work
The estimate for traffic levels in the tunnel was between 9,000 and 13,000 vehicles per day during construction; on the first day of opening, 22,000 vehicles used the tunnel. Current estimates for traffic levels are around 65,000 vehicles per day. These unanticipated high volumes of traffic have increased the wear and tear rate for the tunnel, causing it to close repeatedly for repair and renovation work, which has disrupted traffic in the area for over a decade, and has arguably led to the increase in traffic causing similar problems on the Kingston Bridge.The latest set of repairs, costing as much as the initial outlay for construction, is for a second modern fireproof layer to allow the tunnel to meet European safety standards after St Gotthard and Mont Blanc tunnel fires, along with new air extraction systems and new lighting
Lighting
Lighting or illumination is the deliberate application of light to achieve some practical or aesthetic effect. Lighting includes the use of both artificial light sources such as lamps and light fixtures, as well as natural illumination by capturing daylight...
. For these works, which began in March 2005 and were scheduled to last until at least April 2006, one of the tunnels remains closed during off-peak hours (19:00 to 07:00 daily). This work, however has been beset with problems, and as of August 2007 is still to be completed.
Signs informing road users of the temporary tunnel bore closures have had the completion date blanked out. The roadworks are coinciding with the Hold Your Breath project aiming to add an art
Art
Art is the product or process of deliberately arranging items in a way that influences and affects one or more of the senses, emotions, and intellect....
istic experience to travel through the tunnel. The pedestrian tunnel is also having its years of graffiti
Graffiti
Graffiti is the name for images or lettering scratched, scrawled, painted or marked in any manner on property....
removed as part of its beautification project, however it is an on-going problem, and often is replaced within weeks of being removed.
Breath Holding
A popular game amongst local children, and some adults, is attempting to hold one's breath for the duration of the journey through the Clyde Tunnel. This is possible due to the short length of the tunnel - a car travelling at the 30 miles per hour limit takes 57 seconds to pass through, and at off peak times traffic is often flowing at around 40 mph (a transit duration of 42 seconds). Success is hampered by snarlups (particularly at the interchange on the north end) slowing traffic. The breath-holding game was the subject of Scottish artist Roderick Buchanan'sRoderick Buchanan
Roderick Buchanan is a Scottish artist working in the fields of installation, film and photography.After attending Thomas Muir High School, Buchanan studied at the Glasgow School of Art in the 1980s, where he was part of a group later described as "The Irascibles", which included fellow students...
video Gobstopper, for which he won the Beck's Futures
Beck's Futures
Beck's Futures was a British art prize founded by London's Institute of Contemporary Arts and sponsored by Beck's beer given to contemporary artists....
art prize in 2000.
Pedestrian and Cycle tunnels
Both tunnels are open to pedestrians in both directions. The Eastern tunnel is open to cyclists going southbound, and the Western tunnel to cyclists going Northbound. The Eastern tunnel was closed in December 2008 until March 2009 for a security entry system to be fitted. There is a two gate system at each entry/exit with the gates being opened in response to a 'call' button by a remote operator watching via CCTV. The security gates have failed a number of times since fitted.The Western tunnel was closed in September 2009, apparently so it can also have security gates fitted.