Longest Bridge Making History Discovery Bangla Documentary The World's Longest BridgeDocumentar
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History of The Largest Bridge of The World
Hangzhou Bay Bridge (simplified Chinese: 杭州湾大桥; traditional Chinese: ; pinyin: Hángzhōu Wān Dàqiáo; Wu: Han-tseu-uae du-jiau) is a highway bridge with a cable-stayed portion across Hangzhou Bay in the eastern coastal region of China. It connects the municipalities of Jiaxing and Ningbo in Zhejiang province.
Construction of the bridge was completed on June 14, 2007, and an opening ceremony was held on June 26, 2007. The bridge was opened to public May 1, 2008, after a considerable period of testing and evaluation. The bridge shortened the highway travel distance between Ningbo and Shanghai from 400 km (249 mi) to 180 km (112 mi) and reduced travel time from 4 to 2 hours. At 35.673 km (22 mi) in length, Hangzhou Bay Bridge was among the ten longest trans-oceanic bridges.
The bridge across the Hangzhou Bay was the subject of various feasibility studies for over a decade before the final plans were approved in 2003. An earlier plan placed the bridge further east, closer to the mouth of the bay, which provided an even shorter travel distance between Ningbo and Shanghai. Under this plan, the bridge would begin in the north from Jinshan, a suburb of Shanghai. The government of Shanghai rejected the plan and focused on building the 32.5 km (20 mi)-long Donghai Bridge from Shanghai to its off-shore port at Yangshan in the mouth of the bay. The Shanghai government sought to feature Yangshan as the chief port on China's east coast and refused to allow a cross-bay bridge to be built on its territory, which would improve access to the Port of Ningbo at Beilun. The Zhejiang Provincial Government was forced to build the bridge further to the west on entirely Zhejiang territory. The Hangzhou Bay Bridge connects Cixi, a local-level city that is part of Ningbo Municipality, with Haiyan, a county in Jiaxing Municipality. The Hangzhou Bay Bridge has significantly shortened driving distance between Ningbo and the Yangtze River Delta region and improved the competitiveness of the Beilun Port.
Hangzhou Bay Bridge (section)
The Hangzhou Bay Bridge is of the cable stayed bridge form. This form was chosen for this project because of the strength of the cable stayed bridge in adverse conditions. The bridge was constructed in the Qiantang River and Yangtze River Deltas and Hangzhou Bay, which all experience some of the highest tidal bore forces on the planet. The location of the bridge is also prone to earthquakes, as well as extremely high winds during typhoon season. The bridge form and construction material selections were based on strength against all the different forces the bridge would face.
Many bridges use concrete piles to support the deck but the Hangzhou Bay Bridge took a different approach and used steel piles. This choice was made based on the fact that the steel piles would be much stronger against corrosion from the extremely high tidal forces in the bay. Using the steel piles instead of the concrete piles also made the bridge far more constructible especially in the extremely difficult working conditions that they would be facing. It is not strange to see waves in the bay reaching 25 feet tall. In these conditions it would be almost impossible to construct the bridge without the use of some new construction technology and vehicles. During the construction of the bridge two massive cranes were used, one being 2,200 tons and the other being 3,000 tons. These heavy duty cranes were used to transport massive girders from the shore to the part of the bridge where they would then lift it and put it into place. The steel piles used were also transported using these cranes.
The load paths in this structure are somewhat easy to follow. The gravity load on the bridge as well as the rest of the loading on the deck such as cars are the easiest to follow which is further explained in the qualification as structural art section. The loads on the bridge due to the extreme tides are somewhat difficult to read, but they are clearly accounted for. The steel piles are the structural supports that resist the tidal loads. The piles are driven deep into the sea bed to reduce the movement on them. Having a small moment or force causing bending in the piles keeps the bridge upright. The steel is extremely strong against corrosion and are therefore the best material that could have been used in the piles.
When looking at the loading due to wind loads on the bridge the main portion that is important to analyze is the main spans. Because the two main spans are relative short the wind loading is insignificant.