Boris Johnson recently suggested that the UK could construct a bridge to France, which would cross the English Channel and span at least 20.7 miles (33.3 km):
Mr. Johnson, the British foreign secretary, raised the notion in a summit meeting with French officials on Thursday, according to people briefed on the talks. The two nations agreed to convene a panel to explore big projects, and Mr. Johnson wrote on Twitter: "Our economic success depends on good infrastructure and good connections. Should the Channel Tunnel be just a first step?" The idea generated extensive news coverage and even more ample mockery on social media, where the hashtag #BorisBridge quickly gained popularity.
[...] In 1930, the British Parliament only narrowly rejected a proposed tunnel, and in the 1960s, officials in both countries confidently declared that construction of some kind of crossing was imminent.
But in an island nation whose best defense against continental armies has always been the Channel, generations of military and political leaders saw proposed bridges and tunnels as potential invasion routes. Lately, the Channel Tunnel has beckoned intruders of a different sort: migrants from Africa and the Middle East hoping to reach Britain.
The Channel Tunnel already exists:
Proposed Channel bridges have, at various times, been dismissed as possible threats to navigation. (The Dover Strait, at the Channel's narrowest point, is one of the world's busiest shipping lanes, currently used by over 400 commercial vessels a day, according to the British Maritime and Coastguard Agency.) And even when the political will existed to build a crossing, coming up with the money was always a challenge.
The Channel Tunnel, opened in 1994, cost more than $10 billion to build, and was not heavily used at first, raising questions about whether it was worth the expense. But it now carries more than 10 million passengers and more than 20 million tons of freight annually.
Also at BBC, The Guardian, Channel 4, and CNBC.
(Score: 4, Interesting) by tonyPick on Tuesday January 23 2018, @09:16AM (8 children)
Interesting question - found an answer here:
https://theconversation.com/boris-johnsons-english-channel-bridge-an-engineering-experts-view-90409 [theconversation.com]
(Score: 2) by MostCynical on Tuesday January 23 2018, @09:44AM (2 children)
Thanks.
I was figuring 100m, but I was out by quite a bit.
Tallest overall, so far is in France, at 343m (1125ft) built on land, and only 2400m long (8070ft)
https://en.wikipedia.org/wiki/List_of_tallest_bridges [wikipedia.org]
"I guess once you start doubting, there's no end to it." -Batou, Ghost in the Shell: Stand Alone Complex
(Score: 2, Informative) by Anonymous Coward on Tuesday January 23 2018, @10:00AM
Their estimate makes the absurd assumption that there would be one giant span going all the way across.
That bridge in France isn't one span.
(Score: 2, Insightful) by nitehawk214 on Tuesday January 23 2018, @04:20PM
It would work more like the bridge part of the Chesapeake Bay Bridge Tunnel. It is just slightly above the water level at high tide for most of it, then a couple of big spans to let ships through.
Though, I bet the channel is much deeper than Chesapeake, so either way this would be impracticably expensive.
"Don't you ever miss the days when you used to be nostalgic?" -Loiosh
(Score: 1, Interesting) by Anonymous Coward on Tuesday January 23 2018, @09:55AM
From 1933 through 1937, the USA built the Golden Gate Bridge.
It is 67.1 m above the water at high tide. You want a bridge that is only 5% taller than one we built over 80 years ago? I think this is not a problem.
There is no need to build pylons 500m tall, though this is no obstacle for modern engineering.
You think your English Channel is trouble? While a bridge was being built across the Akashi Strait in Japan, an earthquake moved the towers apart by an additional meter. Earthquakes of magnitude 8.5 are expected.
(Score: 4, Insightful) by GreatAuntAnesthesia on Tuesday January 23 2018, @11:53AM (1 child)
That's if you're going for a suspension bridge. There are other alternatives for the bit that spans the passage. Remember you don't have to bridge the entire channel in one span. A channel bridge would inevitably be many shorter bridges all joined together, and you don't need to have the same bridge type on every span. I think having one or more spans as a lifting bridge would be a good solution.
However I feel duty-bound to point out that all engineering concerns aside, Boris Johnson is still a twat.
(Score: 2) by tonyPick on Tuesday January 23 2018, @03:03PM
True, but the thing about the suspension bridge is you're avoiding columns in the strait itself, and the place you want to build the bridge is busiest international seaway in the world [marineinsight.com], so sticking columns down for conventional bridge supports might cause a host of other problems (according to the conversation article).
On a side note: Neat link to view realtime traffic, if you don't mind javascript: http://www.bognorregisbeach.co.uk/live-shipping-map-english-channel [bognorregisbeach.co.uk]
(Score: 0) by Anonymous Coward on Wednesday January 24 2018, @07:24AM
YOU MUST CONSTRUCT ADDITIONAL PYLONS
(Score: 2) by FatPhil on Wednesday January 24 2018, @10:04AM
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