Difference between revisions of "Jinshajiang Bridge Hutiaoxia"

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For modern expressway bridges, the most recent attempt at designing a nearly towerless suspension bridge was a scheme put forth for the 300 meter deep gorge crossing of the Zhijingje Bridge in Hubei Province that would have had a central span of 540 meters supported by stubby towers approximately 20 meters tall.
 
For modern expressway bridges, the most recent attempt at designing a nearly towerless suspension bridge was a scheme put forth for the 300 meter deep gorge crossing of the Zhijingje Bridge in Hubei Province that would have had a central span of 540 meters supported by stubby towers approximately 20 meters tall.
  
In 1998 Arup, supported by Wilkinson Eyre, won a design competition for the Metsovitikos Bride on the Egnatia Motorway in Greece with a   span between foundations supporting a main span of 565 meters.  The innovative form of the design created difficulties with the main cable deflecting too much above the deck near the ends causing the hangers to go slack.  While solutions were added to the design to create 'virtual saddles' and 'flexing panels' at the ends of the truss deck, additional seismic issues eventually caused the ambitious design to be abandoned in 2001 in favor of a large beam span that was eventually built across the Metsovitikos canyon.  
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In 1998 Arup, supported by Wilkinson Eyre, won a design competition for the Metsovitikos Bride on the Egnatia Motorway in Greece with a 775 meter span between foundations supporting a main span of 565 meters.  The innovative form of the design created difficulties with the main cable deflecting too much above the deck near the ends causing the hangers to go slack.  While solutions were added to the design to create 'virtual saddles' and 'flexing panels' at the ends of the truss deck, additional seismic issues eventually caused the ambitious design to be abandoned in 2001 in favor of a large beam span that was eventually built across the Metsovitikos canyon.  
  
 
The earliest attempt to do away with conventional suspension towers on a large road crossing was for the Lewiston-Queenston Bridge between New York and Canada that was also once the world's longest suspension bridge from 1851 to 1867 with a main span of 317 meters supported by hillside towers just a few meters tall.
 
The earliest attempt to do away with conventional suspension towers on a large road crossing was for the Lewiston-Queenston Bridge between New York and Canada that was also once the world's longest suspension bridge from 1851 to 1867 with a main span of 317 meters supported by hillside towers just a few meters tall.

Revision as of 02:50, 8 September 2016

Jinshajiang Bridge Hutiaoxia
虎跳峡金沙江特大桥
Hutiaoxiazhen, Yunnan, China
853 feet high / 260 meters high
2,513 foot span / 766 meter span
2019


Located just a few kilometers upstream of China's famous Tiger Leaping Gorge, the Jinshajiang Bridge Hutiaoxia and its parallel railway twin will surely become the most photographed and well known suspension bridges in all of Yunnan Province when they are completed in 2019.

The Jinshajiang Hutiaoxia Bridge is the largest and highest of many spectacular bridges on the Lixiang expressway that will connect the popular tourist cities of Lijiang and Shangri-La. What once took three hours on the dangerous local route G214 road will soon be a 90 minute scenic drive high above the Jinsha River gorge and across dozens of deep creek canyons and valleys.

A number of site studies were undertaken before the final Hutiaoxia suspension design was picked. Early designs included a more conventional two tower suspension bridge with a 902 meter main span close to the junction of the Jinshajiang and Chongjiang Rivers and a multi-span extradosed configuration with three spans of 260 meters.

Eventually the engineers decided on a narrower location further downstream that would only require a main span of 766 meters. The only problem was the west side slope was too steep to support a large tower foundation. So they decided to terminate the cables directly into a mountain tunnel ground anchorage thereby creating the largest single tower suspension bridge span in the world.

There have been previous suspension bridges with only one tower and even completely towerless suspension footbridges but none have been built on a scale as large as the Jinshajiang Hutiaoxia Bridge. In China the most famous example of this bridge type is surely the 1983-built Dazi Bridge in Tibet over the Lhasa River with a large span of 415 meters and a total length of 500 meters with an anchorage high up on a cliff that required cable stays on the high end.

For modern expressway bridges, the most recent attempt at designing a nearly towerless suspension bridge was a scheme put forth for the 300 meter deep gorge crossing of the Zhijingje Bridge in Hubei Province that would have had a central span of 540 meters supported by stubby towers approximately 20 meters tall.

In 1998 Arup, supported by Wilkinson Eyre, won a design competition for the Metsovitikos Bride on the Egnatia Motorway in Greece with a 775 meter span between foundations supporting a main span of 565 meters. The innovative form of the design created difficulties with the main cable deflecting too much above the deck near the ends causing the hangers to go slack. While solutions were added to the design to create 'virtual saddles' and 'flexing panels' at the ends of the truss deck, additional seismic issues eventually caused the ambitious design to be abandoned in 2001 in favor of a large beam span that was eventually built across the Metsovitikos canyon.

The earliest attempt to do away with conventional suspension towers on a large road crossing was for the Lewiston-Queenston Bridge between New York and Canada that was also once the world's longest suspension bridge from 1851 to 1867 with a main span of 317 meters supported by hillside towers just a few meters tall.

Many footbridges around the world have been built with no cable towers. One famous example being the the Grand Canyon Black footbridge over the Colorado River in Arizona.

If being the world's largest single tower suspension bridge was not enough, the Hutiaoxia Bridge will also have China's first completely tunneled bridge entrance and exit roads on the north, Shangri-La side. Steep switchbacks will carry drivers to and from the bottom of the canyon where the local road will allow access to the famous Tiger Leaping Gorge scenic spot. But these switchbacks might not be around forever. Both Jinshajiang Hutiaoxia bridges were designed to allow reservoir water over 200 feet to fill beneath them in case the planned Tiger Leaping Gorge Dam is constructed just a couple of kilometers downstream. Environmental groups and tourism businesses in the region are fighting the dam to preserve the natural state of the river and the gorge and with so many tourists vital to the economies of both Lijiang and Shangri-La, there is a good chance it will never be built.

The total length of the Jinshajiang Bridge Hutiaoxia is 1,020 meters including six approach spans of 41.5 meters. The one tower on the south side is 149 meters tall.


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Jinshajiang Bridge Hutiaoxia satellite image.


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Jinshajiang Bridge Hutiaoxia location map.


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