COWI has been awarded two significant prizes in a design competition for the 15.2m diameter Chongming tunnel in China. The 8km long twin bore road tunnel is planned to be the largest diameter bored tunnel in the world.
The future owner of the tunnel, Shanghai HucChong River Investment and Development Co. Ltd., put together an evaluation committee of 15 Chinese and international experts to evaluate submissions.
Participating in a joint venture with Shanghai based consultants SMEDI and the Hong Kong office of Ove Arup, COWI submitted a preliminary overall design, as well as more specialised studies for the tunnel under the Yangtze River from northern Shanghai to the island of Chongming.
A Japanese group made up of Nikken Sekkei Civil Engineering, Pacific Consultants Company and Obayashi Corporation acted as subconsultants.
The tunnel is designed to house a three lane motorway and COWI came first for “permanent tunnel construction and documentation for 100 years [life]” and second place for overall project design.
Although there was not a contract award tied to the competition, the prizes consisted of payments for part of the work done for the competition. With the tunnel expected to be tendered as a design and construct contract later this year Søren Degn Eskesen, chief specialist for COWI, agreed the competition could only increase COWI’s reputation in the region and result in it being in a stronger position when the project goes out to tender.
To accommodate six lanes of traffic, the twin bores will have a 15.2m external diameter, 0.7m larger than current record holder, the Dutch Groene Hart Tunnel (T&TI, February p10). Eskesen said: “The tunnel is to be built in extremely difficult soil conditions consisting of soft deposits of clay, silt and sand.” He said that COWI would act upon experience gained in the mid 1990s when it was consultant for a wastewater tunnel a few kilometres upstream. He added that COWI currently had no preference for a TBM supplier, but it was likely to be a slurry type TBM.
