| Hangzhou Bay Bridge | |
|---|---|
| Carries | Six lanes of G15 Shenyang–Haikou Expressway and G92 Hangzhou Bay Ring Expressway |
| Crosses | Hangzhou Bay |
| Locale | Jiaxing / Cixi City People's Republic of China |
| Total length | 35.673 km (22 mi) |
| Longest span | 448 m (1,470 ft) |
| Construction begin | June 8, 2003 |
| Construction end | June 14, 2007 |
| Opened | May 1, 2008 |
| Toll | 80 yuan |
| Location of bridge | |
Hangzhou Bay Bridge (simplified Chinese: 杭州湾大桥; traditional Chinese: 杭州灣大橋; pinyin: Hángzhōu Wān Dàqiáo) is a long 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. At 35.673 km (22 mi) in length, Hangzhou Bay Bridge is one of the longest trans-oceanic bridges in the world. Construction of the bridge was completed on June 14, 2007,[1] and an opening ceremony was held on June 26, 2007, to great domestic media fanfare. The bridge was not opened to public use until May 1, 2008, after a considerable period of testing and evaluation.[2] The bridge shortened the highway travel distance between Ningbo and Shanghai from 400 km (249 mi) to 280 km (174 mi) and reduced travel time from 4 to 2.5 hours.[3]
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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.
Because of the many difficulties facing such a tremendous build, almost 600 experts spent nearly a decade designing the bridge. Even after nearly a decade of design, studies, and planning, many different challenges were encountered, the first being the challenge of offshore construction. As a solution, several parts of the bridge had to be completed on land and then transported to the area for which they were built. Some components that were constructed using this process were piers, box girders (bridge panels), and even the bridge foundations.[4]
Another construction challenge involved the weather in the region. Wang Yong, chief director of the Hangzhou Bay Trans-Oceanic Bridge Construction Command Post, described the bridge as being built "in the world's most complicated sea environment, with one of the three biggest tides on Earth, the effect of typhoons and the difficult content of the sea soil."[4] Erosion of materials and cracking and bubbling of any concrete components became a large problem. To combat bubbling and eventual holes, engineers used a cloth-covered template over the concrete. This would improve the color and density of the pieces, making them both more aesthetically pleasing and sturdier. To reduce cracking, engineers used low-strength early-stretching technology when constructing box girders. This technology involves casting (molding) the girder, or bridge panel, letting it harden for no more than three days, and then squeezing it before it reaches its full density. This gives the girder more room to stretch after the bridge is constructed, preventing cracks in the concrete over time.[4]
The third major challenge faced by designers and engineers was an area of toxic methane gas that was discovered roughly 50 meters underground below the location of the bridge. No drilling could be completed before the gas pressure was alleviated. To do this, steel pipes measuring 60 cm in diameter were inserted into the ground, slowly releasing the methane six months prior to drilling.[5]
A 10,000 square metre service centre called Land between the Sea and the Sky (Chinese: 海天一洲, Pinyin: Hǎitiān Yīzhōu) is built in the middle of the bridge. This centre contains a resting area, a restaurant, a gas station, a hotel, a conference room, and a lookout tower, which serves as a tourist attraction to watch the tide. The service centre is built on an island, which is a platform resting on piers to avoid obstructing the sea current in the bay.[6]
The service centre was slightly damaged in a fire on the March 23, 2010[7], but opened to tourists on December 19, 2010[8].
Hangzhou bay bridge website http://www.hangzhoubaybridge.com/bridge.asp
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