As Hong Kong-Macau Tunnel Progresses, Denmark Floats a Record Breaker
Chinese contractors have hit the halfway mark of building an immersed-tube tunnel (ITT) between Hong Kong and Macao that, when opened in 2016, will be the world's longest, at 29.6 kilometers. But engineers in Denmark are in the final procurement phase for a project that will be three times longer: a Denmark-Germany ITT across the Fehmarnbelt waterway.
Final price bids for the 17.6-km-long Fehmarnbelt road-and-rail ITT are due this December, and work will start next summer, says Steen Lykke, technical director at Femern A/S, the government-owned Danish company in charge of the $7.6-billion crossing.
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The tunnel will link Denmark's Rødbyhavn and Puttgarden, which is located on the north side of the German island of Fehmarn. It will include 79 standard ITT elements, plus 10 deeper special units to house equipment at 1.8-km intervals. Weighing around 73,500 tonnes each, the 217-meter-long standard units will be about 42 m wide and 9 m tall.
The two biggest contracts will cover the northern and southern halves of the tunnel. Dredging work, including the 18-km-long, 80-m-wide and 10-m-deep trench, comprises another contract. The fourth contract covers portal structures and other land facilities on both coasts.
Firms from Belgium, Denmark, France, Germany, Italy, the Netherlands, South Korea and Spain formed nine consortiums that submitted 17 technical bids for the four contracts.
Among non-Scandinavian main contractors are Germany’s Hochtief Solutions A.G., Ed Züblin A.G., Wayss & Freytag Ingenieurbau A.G. and Max Bögl Bauunternehmung.
The Netherlands is represented by Boskalis International B.V., Van Oord Dredging and Marine Contractors B.V., and units of Royal Bam Group.
From the U.S., Great Lakes Dredge & Dock Co., Oak Brook, Ill., is a subcontractor for one team. The U.K. is represented by London-based design firms Capita Symonds PLC and Mott MacDonald Group, each advising different bidders.
Femern A/S and the contractors are now beginning "competitive dialogue," which is a European Union negotiations procedure designed for projects that are complicated or require innovation.
The process aims “to make sure [the contractors] have understood our requirements and that we have understood their proposals,” says Lykke. Bids are based on the owner’s illustrative designs, which allow for variations within constraints, Lykke adds.
Constraints include the need to cast entire sections of the 79 standard elements in single pours to ensure watertightness, says Lykke. While the work requires specialist skills, the contractors also must demonstrate the capacity to handle the scope of work and extended logistics, he adds.
For example, the two tunnel contractors will work from opposite coasts, 18 km apart, while sharing the same element production yard, located on reclaimed land near landfall at Rødbyhavn on the Danish side, says Lykke. Around 3 million cu m of reinforced concrete will be poured at the site.
By the time contracts are awarded next year, the two countries expect to have provided all necessary approvals. Permitting takes the form of legislation in Denmark and regulations in Germany, says Lykke.
Chinese Connection
Some 9,000 km away, meanwhile, a consortium led by China Communications Construction Co. Ltd. (CCCC) is placing elements—each weighing over 75,000 tonnes—on the 6-km-long ITT that will form part of the road crossing of the Pearl River estuary, from Hong Kong to Macao and Zhuhai, according to a report from the site.
The 29.6-km, mostly elevated link to the Hong Kong border is due to open in about two years at an estimated cost of $6.1 billion. It is being procured by Hong Kong-Zhuhai-Macao Bridge Authority, which is controlled by the government of Guangdong and the Special Administration Regions of Hong Kong and Macao.
The tunnel will run between two 650-m-long artificial islands, one of them on the Hong Kong border. The link will continue onto dry land in Hong Kong on a 9.4-km-long viaduct, which is being financed by Hong Kong and built by local subsidiaries of Paris-based Bouygues Construction S.A. and China Harbour Engineering Co. Ltd.
CCCC is close to completing the casting of the 13th of the project’s 33 elements. It immersed the 10th in late March, according to Tommy Olsen, chief project manager at Denmark's COWI A/S, the contractor’s international design firm. A local company is handling detailed design, he adds.
Weighing over 75,000 tonnes each, the 180-m-long elements are 38 m wide and 10 m tall.
Unexpected sedimentation levels complicated the four-day operation to place the first ITT element in early May 2013, according to Netherlands-based Tunnel Engineering Consultants, which is advising the Chinese government. Otherwise, says Olsen, “construction is on track.”
