Piling of Yongding New River Extra Large Bridge to be completed in May 2009

Source of Article: http://english.enorth.com.cn/system/2009/03/25/003939150.shtml

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The northern section of Haibin Dadao (Phase II) with a total investment of over 1.7 billion yuan is under smooth construction, and currently the Yongding New River Extra Large Bridge is undergoing the concrete placement of 200 bored piles, which is expected to totally complete by the end of May 2009. The constructors use “sediment separator” to increase the quality of construction due to the extra length and diameter of piles which require high accuracy.

Haibin Dadao is the trunk line from north to south of the road system framework “14 horizontal and 8 vertical lines” along the beach. The northern section of Haibin Dadao (Phase II), to be constructed by the CCCC First Harbor Engineering Company Ltd., will start from the flyover intersection of Line 3 to Container Terminal on the south, span across the estuary of North Pond of Yongding New River on the north, and connect to the northern section of Haibin Dadao nearly 1 km north from Chengtougu. The project is 9.11km all long, completely according to the standard of express highway, allowing the traveling speed not exceeding 80km/h. Where the section between the flyover intersection of Line 3 to Container Terminal and the planned Beijing-Hong Kong Railway is two-way 8-lane express highway, and the section between the planned Beijing-Hong Kong Railway and the Chengtougu is two-way 6-lane express highway. The section from the flyover intersection of Line 3 to Container Terminal and the Chengtougu is trestle bridge section, the trunk line bridge in the air is 8.58km long, and the road section on the ground is 0.53km long in total.

Yongding New River Extra Large Bridge is the key node in the northern section of Haibin Dadao (Phase II), as an important passage connecting Beijing, Tianjin and Hebei, the northern section of Tianjin Haibin Dadao will be constructed according to the standard of express highway. This Extra Large Bridge will apply bored pile foundation, with the longest pile of 88m, and shortest pile of over 60m, and maximum pile diameter of 1.8m. Such piles have high requirements for the pore forming verticality, hole foe sediment thickness control, and a slight neglect may result in diameter shrinkage, infirm step, buried penstock, interlace or broken pile.

For this purpose, constructors adopt a “sediment separator” to reduce sediment charge, and produce reinforcement cage on a whole in place of by segment and apply other advanced techniques of construction to increase the quality and progress of construction. The constructors drill hole firstly, then place the reinforcement cage covered by a pile casing into the hole. Then the constructors place concrete, until the concrete around the pile casing becomes solid, and then lift the casing up to carry out further placement of concrete. In such a way, it is possible to keep off sludge and reduce sediment charge, and increase the quality of construction.

The engineers said that the Yongding New River Extra Large Bridge requires 200 bored piles to be completed fully by the end of May 2009, and then comes release of steel cofferdam and construction of bearing platform and other processes.