Strait of Gibraltar crossing

The Strait of Gibraltar

A Strait of Gibraltar crossing is a hypothetical bridge or tunnel spanning the Strait of Gibraltar that would connect Europe to Africa.

Bridge

Several engineers have designs for a Gibraltar Bridge on various alignments and with differing structural configurations. Professor T.Y. Lin’s proposal for a crossing between Point Oliveros and Point Cires featured a 14-kilometre length, deep piers, and 5000-metre spans, far exceeding the longest current bridge span.^[1]

In 2004 United States architect Eugene Tsui published his concept of a floating and submerged bridge connecting at a three mile wide floating island in the middle of the Mediterranean Sea.^[2]

In 2004 The Science Museum included an image of the concept of the proposed Gibraltar Straits road bridge.^{[3][clarification needed]}

Futurist author Arthur C. Clarke described a bridge across the Strait in his 1979 science fiction novel The Fountains of Paradise.

Tunnel

Various Gibraltar tunnels have been proposed.

The Spanish and Moroccan governments had been jointly investigating the feasibility of a tunnel underneath the strait, similar to the Channel Tunnel between the UK and France. However, 2008 geological studies cast doubt on its practicality.^{[citation needed]}

The idea of a tunnel for petrol/diesel powered road vehicles has been discounted due to the currently insurmountable engineering challenge of ventilation to remove exhaust gases from a tunnel some 14 kilometres (8.7 miles) long.^{[citation needed]} A three-year study for a railway tunnel was announced in 2003.^{[clarification needed]} The strait depth extends to 900 metres (3000 ft), and it is about 14 kilometres (8.7 miles) wide at its narrowest point. The project would be financed by two publicly-owned companies in Spain and Morocco, with the assistance of the European Union.^{[4][clarification needed]}

A report on the feasibility of the tunnel is due to be presented to the EU in 2009.^[4][5][6]

Planning

In December 2003, Spain and Morocco agreed to explore the construction of an undersea rail tunnel to connect their rail systems. In late 2006, Lombardi Engineering Ltd, a Swiss engineering and design company, was retained to draft a design for a railway tunnel.^[7] According to the company, the main differences between the construction of this tunnel and that of the Channel Tunnel, linking France and Great Britain, are the depth of the sea and the geological conditions. The area under the Strait is less stable than that under the English Channel, as an active major geologic fault, the Azores-Gibraltar Transform Fault, bisects the Strait, and severe earthquakes have occurred in the area. The presence of two very deep Quaternary clay channels in the middle of the Strait also makes construction complex,^[4] causing doubts about the feasibility of the project and proposals for an exploratory tunnel.^[8]

It is projected to carry 9 million passengers in its first year of operation, expected to be 2025. No official figures about the cost of the project had been announced by 2007, but previous estimates were at least five billion Euros.^[9]

Technical aspect

The Strait of Gibraltar opening into the Mediterranean Sea, showing the proximity of the two nations. Spain is to the left on the horizon (faintly), and Morocco to the right on the horizon.

The twin rail tunnel would be 40 kilometres (25 mi) long, 300 metres (980 ft) deep,^[5] and its construction could take 15 years. Initially a single rail tunnel and a smaller service tunnel are envisaged. A second tunnel would be built if required.^{[clarification needed][4]}

The tunnel would be standard gauge 1,435 mm (4 ft 8+¹⁄₂ in) to match the proposed construction and conversion of significant parts of the existing Iberian gauge to standard gauge.^[10][11] The line is likely^[who?] to be electrified at 25 kV AC, the same as Spanish AVE lines, despite both countries having 3 kV DC electrification systems, as the 25 kV AC is more modern and requires less infrastructure.

The tunnel would have linked Cape Malabata near Tangier with Punta Paloma 40 km west of Gibraltar.^[12] This link will be 300 metres (around 900 feet) deep. The original link was planned to link the two continents via the narrowest part of the strait but this idea was dismissed as it is 900 metres (around 2700 feet) deep. Even 300 m is deep since the deepest undersea tunnel, the Eiksund tunnel is 287 m (942 ft) below sea level.

It is likely^[who?] that a branch from the Madrid-Seville AVE line would connect to the tunnel at the north end. There were also proposals^[who?] to develop a high speed network in Morocco. Terminals would need to be constructed for trans-shipment of road vehicles, like those at Cheriton and Frethun.

See also

• Extreme Engineering
• Channel Tunnel
• Strait of Messina Bridge
• Bering Strait crossing
• Strait of Sicily Tunnel

References

External links

• 5 most ambitious bridge designs of today. January 7, 2008
• The original Trans-Global Highway proposal. Frank Didik. 2006
• "Gibraltar: Tunnel under troubled waters". 30 June 2008. http://layijadeneurabia.com/2008/06/30/gibraltar-tunnel-under-troubled-waters/. Retrieved on 3 February 2009. 
• A man from Ticino to link Europe and Africa
• "Website of the project of the fixed link through the Strait of Gibraltar". Archived from the original on 2007-05-16. http://web.archive.org/web/20070516142231/http://www.secegsa.com/eng/index-eng.aspx. Retrieved on 3 February 2009.