SECTION 3
Passage-5
Read the text below and answer Questions 28-40.
The World's Highest Bridges
A The Siduhe River Bridge
Located about eighty kilometres south of the famous Three Gorges region of the Yangtze River in China's mountainous Hubei Province, the Siduhe suspension bridge is just one of several amazing structures on the last 483 kilometre link of the 2,175 kilometre long West Hurong highway that now connects Shanghai on the Pacific coast with the cities of Chongqing and Chengdu in the west. With a roadway 496 metres above the water, the Siduhe River Bridge is, as of 2014, the highest bridge in the world. One unique aspect of The Siduhe River Bridge's construction relates to its extreme height, remoteness and inaccessibility. Due to all this, the building engineers decided to experiment and, instead of using a blimp or helicopter to drag the first pilot line across the gorge, they used a rocket.
B The Hegigio Gorge Suspension Bridge
Located deep in the Southern Highlands Province of Papua New Guinea is the Hegigio Gorge Suspension Bridge, the highest pipeline bridge in the world. Some may argue that the Hegigio Gorge Bridge is not a true bridge, since it was not built for people, but for an oil pipeline. The bridge is a major component of the Southeast Mananda oil field infrastructure, an inaccessible expanse of oil that was discovered in 1991. The small size of the field and the extremely remote, jungle terrain made it a difficult petroleum project to undertake with many technical obstacles to overcome, the bridge being one of them. During construction, the north side of the bridge was difficult to reach, since there was no road access in place as there was on the south side. The first two cables were strung across by a helicopter, while successively thicker cables were then winched across. Another construction hurdle came from the harsh weather, which even today can be problematic to the operation of the pipeline. One oddity of the bridge is that there is no pedestrian walkway on the bridge. If necessary, personnel access for maintenance is made possible by a trolley that rides along two rails.
C The Baluarte River Bridge
The Baluarte River Bridge is not only the highest bridge in North America, but the highest cable-stayed bridge in the world, surpassing the Millau Viaduct in France. It is the crown jewel of the greatest bridge and tunnel highway project ever undertaken in North America. The old road between the Pacific coast and the interior of Mexico is known as the “Devil's Backbone”, and the road that created a safer and more direct route necessitated seven very high bridges and sixty-one tunnels; the Baluarte River Bridge is the highest of the bridges.
D The Balinghe River Bridge
With a height of 370 metres from deck to water, the Balinghe River bridge is the second highest bridge in China. It is unique for having the second longest span length with a distance between towers of 1088 metres. The reason why Balinghe River Bridge has this unusual span length relates to the luck that the Chinese associate with the number 8, which sounds like the Mandarin word for “prosperity'. The bridge was meant to be a concrete beam bridge, but the lack of sand suitable for concrete in the area made this plan too expensive, as sand would have had to be transported to the building site. As a result, a suspension bridge was constructed, which is an excellent type of bridge to build across a large gap. The Balinghe River Bridge has two towers, which are easily supported by the main steel cables that curve from one tower to the other. The curving main steel cables also hold other cables (each is known as a suspender), which go down from the main steel cables to the road deck. It is unusual in that, at each end, the main steel cables continue into the ground and are attached to a concrete anchor that provides extra stability and support. Another peculiarity of the bridge is that, as it is situated between two mountain ranges, there is frequent cloud cover, which sometimes makes it appear to be floating among the clouds.
E The Chenab River Bridge
There is probably no other natural barrier on earth that has been more formidable to railway engineers than the Himalayan mountain range that stretches across northern India. When construction began on the Chenab River Bridge, the engineers experienced extensive delays due to difficult geology, access problems, tunnel excavation difficulties and labour disputes. The bridge is not yet open, but, when it is, it will be the most expensive stretch of India's 64,374 kilometre railway network. The Chenab River Bridge will have busy traffic, as it is located fewer than sixteen kilometres north of the busy tourist town of Katra, which, due to its proximity to the Vaishno Devi, is the second most visited religious shrine in India. Being in Kashmir, the Chenab River Bridge is also very near the conflict area between India and Pakistan. For this reason, there is a constant armed guard present at the bridge and this will also remain after completion.
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