3 ms·

A response from the Telegraph. http://www.telegraph.co.uk/travel/lists/worlds-longest-bridges/ http://www.telegraph.co.uk/travel/lists/worlds-longest-bridg...

A response from the Telegraph. http://www.telegraph.co.uk/travel/lists/worlds-longest-bridges/ http://www.telegraph.co.uk/travel/lists/worlds-longest-bridg... For comparison they show the following list. Where | Length in kilometres Danyang–Kunshan Grand Bridge, China 165 Changhua-Kaohsiung Viaduct, Taiwan 157 Tianjin Grand Bridge, China 114 Hong Kong-Zhuhai-Macau Bridge, China 55 Bang Na Expressway, Thailand 54 Lake Pontchartrain Causeway, USA 38 > 'Boris Bridge', UK-France 35 In light of all these other megastructures the proposed Boris Bridge doesn't sound too unreasonable? Considering the two economies it would link… Linking Ireland and the UK, that'd be another matter entirely.

pouetpouet 9y ago
The Danyang-Kunshan is mainly over land. It's an elevated railway line. It does cross the Yangcheng Lake, but that part is only 9km long. It's not a suspended bridge, there are piles every 80m. Not suitable for heavy maritime traffic. The lake has an average depth of 2m. https://www.lakepedia.com/lake/yangcheng.html https://www.lakepedia.com/lake/yangcheng.html It's not comparable as a channel crossing. https://en.wikipedia.org/wiki/Danyang%E2%80%93Kunshan_Grand_Bridge https://en.wikipedia.org/wiki/Danyang%E2%80%93Kunshan_Grand_... Likewise the depth of Jiaozhou bay is 10 to 15m. The channel is 45m deep between Calais and Dover (the shortest and shallowest crossing). Moreover the strait of Dover (or Pas de Calais in french) is the busiest shipping lane in the world http://i.dailymail.co.uk/i/pix/2014/05/22/article-2636152-1E1A483000000578-594_964x516.jpg http://i.dailymail.co.uk/i/pix/2014/05/22/article-2636152-1E...
maxerickson 9y ago
Some of those can't admit any ships, never mind the biggest ships on the ocean. For example, the Lake Pontchartrain Causeway impacts quite small boats: https://en.wikipedia.org/wiki/Lake_Pontchartrain_Causeway#/media/File:Lake_Pontchartrain_Causeway.jpg https://en.wikipedia.org/wiki/Lake_Pontchartrain_Causeway#/m... That's a completely different project than something that won't impact traffic that needs 50 or 70 meters of clearance.
make3 9y ago
the problem they say is that this would be on one of the world's most active shipping lane and that boats would need to be able to pass under the bridge, requiring it to be much higher than the other bridges of that list
kibwen 9y ago
The engineer's statements linked by the parent poster mentions Danyang-Kunshan: "the longest bridge in the world is the Danyang–Kunshan Grand Bridge in China. It is mostly a conventional bridge made from columns sunk into the seabed, although it has a cable-stayed section. The bridge is 165km long (just over 100 miles) but the short distance between the columns would not do for the busy Channel."
tankenmate 9y ago
The size of ships and number of ships going through the English channel are much larger than any of the bridges listed above apart from possibly the HK <-> Macau bridge.
mastax 9y ago
The only bridge on that list even remotely comparable is the Hong Kong-Zhuhai-Macau Bridge. The rest are essentially elevated highways which are almost entirely over land. I am not a civil engineer so this is just some uninformed speculation: - The channel goes to about 45m deep between Dover and Calais, while the path of the HK bridge only goes to about 20m depth. - The bay formed by the Pearl River is more enclosed and protected from weather than any part of the channel. - The bridge would need sections elevated high enough for future mega container ships. - The HK bridge cost $15.9b. I'd expect the channel bridge to cost much more. It might be cheaper to just build another tunnel. Edit: and, of course, by the time I finish this comment there are 10 more saying basically the same thing.
- maxerickson 9y ago
  The Hong Kong-Zhuhai-Macau includes a section of tunnel, so it doesn't need the height above the water that a pure bridge crossing would require.

pouetpouet 9y ago

The Danyang-Kunshan is mainly over land. It's an elevated railway line. It does cross the Yangcheng Lake, but that part is only 9km long. It's not a suspended bridge, there are piles every 80m. Not suitable for heavy maritime traffic. The lake has an average depth of 2m. https://www.lakepedia.com/lake/yangcheng.html https://www.lakepedia.com/lake/yangcheng.html It's not comparable as a channel crossing. https://en.wikipedia.org/wiki/Danyang%E2%80%93Kunshan_Grand_Bridge https://en.wikipedia.org/wiki/Danyang%E2%80%93Kunshan_Grand_... Likewise the depth of Jiaozhou bay is 10 to 15m. The channel is 45m deep between Calais and Dover (the shortest and shallowest crossing). Moreover the strait of Dover (or Pas de Calais in french) is the busiest shipping lane in the world http://i.dailymail.co.uk/i/pix/2014/05/22/article-2636152-1E1A483000000578-594_964x516.jpg http://i.dailymail.co.uk/i/pix/2014/05/22/article-2636152-1E...

maxerickson 9y ago

Some of those can't admit any ships, never mind the biggest ships on the ocean. For example, the Lake Pontchartrain Causeway impacts quite small boats: https://en.wikipedia.org/wiki/Lake_Pontchartrain_Causeway#/media/File:Lake_Pontchartrain_Causeway.jpg https://en.wikipedia.org/wiki/Lake_Pontchartrain_Causeway#/m... That's a completely different project than something that won't impact traffic that needs 50 or 70 meters of clearance.

make3 9y ago

the problem they say is that this would be on one of the world's most active shipping lane and that boats would need to be able to pass under the bridge, requiring it to be much higher than the other bridges of that list

kibwen 9y ago

The engineer's statements linked by the parent poster mentions Danyang-Kunshan: "the longest bridge in the world is the Danyang–Kunshan Grand Bridge in China. It is mostly a conventional bridge made from columns sunk into the seabed, although it has a cable-stayed section. The bridge is 165km long (just over 100 miles) but the short distance between the columns would not do for the busy Channel."

tankenmate 9y ago

The size of ships and number of ships going through the English channel are much larger than any of the bridges listed above apart from possibly the HK <-> Macau bridge.

mastax 9y ago

The only bridge on that list even remotely comparable is the Hong Kong-Zhuhai-Macau Bridge. The rest are essentially elevated highways which are almost entirely over land. I am not a civil engineer so this is just some uninformed speculation: - The channel goes to about 45m deep between Dover and Calais, while the path of the HK bridge only goes to about 20m depth. - The bay formed by the Pearl River is more enclosed and protected from weather than any part of the channel. - The bridge would need sections elevated high enough for future mega container ships. - The HK bridge cost $15.9b. I'd expect the channel bridge to cost much more. It might be cheaper to just build another tunnel. Edit: and, of course, by the time I finish this comment there are 10 more saying basically the same thing.

maxerickson 9y ago
The Hong Kong-Zhuhai-Macau includes a section of tunnel, so it doesn't need the height above the water that a pure bridge crossing would require.