Shanghai Container Port Heads to Sea To Handle Deep-Draft Ships
By spring, work had progressed enough for managers and contractors to power up offices and sleeping quarters on the islands. Until then, they stayed on work ships or shuttled to the mainland. The last of the islands’ 1,200 inhabitants also had been relocated by then.
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| NEW LAND Container facilities will cover reclamation. |
The initial key construction issues centered on steel pipe corrosion, soft soils, land reclamation and construction of a seawall and retaining dike, within which land reclamation is performed.
The first task for Shanghai Dredging Corp. and Shanghai Port Construction Corp. was to build the 1.2-km-long northern retaining dike that connects the two islands. Working in 28-m depths, the contractors formed the dike with block stone and protected it with mattresses of sacked sand and rock armor, building it to 9 m above sea level. Rock has been blasted from the surrounding islands. "The technique has been used in shallow waters of the Yangtze," says Yiping Zhou, deputy general manager of Shanghai International Engineering Port Consultants Ltd., the jobs’s consulting engineer.
When the dike was finished in February 2003, dredges began reclaiming 25 million cu m of land for the first berthing area. Gui says the job was complicated by 2-m-per-second water flow in the area.
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| TAKING SHAPE Terminal quay is built on 60-m-long piles to provide deepwater access for container ships as reclaimed land creeps forward. |
As contractors compact reclaimed land, Shanghai Port Construction Corp. and SHEC are moving on a massive pile-driving operation for the quay and marine terminal. "The selection of profiles is done by the profile of the seabed," says Gui. Most are steel pipe piles ranging in diameter from 1.2 to 1.7 m. Length varies, but the longest reach 63 m, driven through layers of sand, silt and clay to bedrock almost 40 m beneath the seabed.
The 488-m-long terminal is based on a 37-m-wide concrete platform, supported by piles. Gui and other planners worried about corrosion from the marine environment, but he says the project has benefited from advances in protective coatings. United Coatings, Spokane Valley, Wash., won a contract to protect the piles. From a yard in Shanghai, workers apply two different coatings to 30-m sections that are then welded to 30-m uncoated sections. The uncoated sections pierce the seabed.
The quay structure is made of 10-m-long concrete bents. Precast segments are barged from the mainland, but batch plants on site accommodate the cast-in-place platform slab.
Working concurrently, a second team of contractors is driving piles and placing piers for the 32-km Donghai Bridge. A box-girder causeway for most of the distance, the link will rise to a five-span cable-stayed crossing to provide 40 m of clearance over two major shipping channels. Shanghai Construction Group General Co. already has finished two steel deck structures. The cable-stayed spans, anchored by four 43-m-high towers, will vary in length–two 73-m spans, two 132-m spans and one 420-m span. A contract to supply and install cables has not yet been signed, says Gui.
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| RISING Bridge work just got costlier. |
While port construction in the islands has gone smoothly so far, bridge contractors recently said the crossing faced cost overruns that could reach $350 million. Local papers quoted Tan Guoshun, deputy general manager of China Zhongtie Major Bridge Engineering Group, as saying the increase is tied to unanticipated difficulty in driving piles into the seabed. The contractor had to purchase additional equipment, including a crane that could lift 1,600-ton loads, to continue the job. The casting yard is located on an island 30 km from the bridge channel. All precast segments are transported to the site by barge. China Zhongtie holds contracts to construct piers and 70-m-long precast segments.
When the project is fully fitted out by developing two other islands in the archipelago in 2020, project officials expect total costs to reach $18 billion to $20 billion. Already, other projects to feed the port are beginning. Officials announced in June that work would soon begin on a new freight railway in Shanghai’s Pudong area that would haul cargo containers directly from the mainland transfer center. Eventually, port officials plan to build a second parallel crossing to provide direct rail access to the Yangshan Deepwater Terminal.
(Photos courtesy of Shanghai International Port Engineering Consultants Ltd.)
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