Engineers wait with bated breath for a call they may never get. Earlier this year, the United Kingdom’s Foreign Secretary, Boris Johnson, proposed a 22-mile bridge to span the English Channel.
Eleven tunnel boring machines and engineering expertise created the 50.45 kilometer (31.35 mile) Channel Tunnel link between England and France.The tunnel took five years to build with a total of 13,000 workers from both England and France. If the building of a bridge is announced it would mean a sizeable payday for engineers attached to the project.
Some have dismissed Johnson’s intention to build the bridge - calling it a fantasy that will never come to fruition. However, Channel Tunnel operators Eurotunnel have expressed interest in the project.
Speaking in the House of Commons, Johnson said:
“It is a curiosity that two of the most powerful economies in the world, separated by barely 21 miles of water, are connected by only one railway line. And I think it is a matter for legitimate reflection by our two countries on the way forward.”
The bridge would be an impressive feat, not just considering the engineering prowess it would involve, but because it would be a post-Brexit achievement for the country which is due to leave the European Union, but still retain its business connections with France.
What they’ll need
If the plan to build the bridge goes forward, engineering professionals will either be tasked with creating a cable stayed bridge or a suspension bridge. There is just one glaring problem that is already causing speculators some consternation: boats.
Wanda Lewis, Emeritus Professor in Civil Engineering at the University of Warwick took to The Conversation, to explain. She writes:
“The channel is between 40m and 60m deep and some passenger ships are more than 70m tall. So to let ships pass underneath, the pylons supporting the bridge would have to be around 150m tall. To support the cables you would have to add pylons above the deck, which would mean a total pylon height well above 500m. Again, nothing this tall has ever been built.”
If the bridge does get built, it will be the world’s tallest bridge, and may just get recognition as a marvel of the modern world. However, with height comes wind and this strengthens with greater height. The bridge could be poised to deal with a number of wind-related engineering challenges.
With the longest bridge in the world as a case study, the Danyang-Kunshan Grand Bridge in China, the Daily Mail estimates that the bridge would cost approximately £824 million (USD 1.150 billion).
The Boris Bridge - as it has now been humorously dubbed - has received a great deal of backlash. The UK Government may indeed scrap the idea, but they are not ruling out the possibility of another tunnel.
Eurotunnel maintain that building a second link to England is not a matter of ‘if’ but a matter of ‘when’. Chief Executive of Eurotunnel Jacques Gounon wrote in a letter:
“The idea of a second fixed link is something that we regularly consider in our long term plans, and we would be delighted to engage with your officials to explore the possibility further.”
Lewis, Wanda. “Boris Johnson's English Channel Bridge: an Engineering Expert's View.” The Conversation, 12 Mar. 2018, theconversation.com/boris-johnsons-english-channel-bridge-an-engineering-experts-view-90409.
Ravenscroft, Tom. “Eurotunnel ‘Very Interested’ in Boris Bridge between England and France.” Dezeen, Dezeen, 14 Feb. 2018, www.dezeen.com/2018/02/14/eurotunnel-channel-tunnel-interested-boris-bridge-england-france/.