East Tsing Yi Viaduct - A tough schedule to erect a concrete deck 7 km long

At the end of 2004, the Hong Kong Highways Department awarded the contract for the construction of the East Tsing Yi approach viaduct to Stonecutters Bridge, to Dragages Hong Kong, Bouygues Travaux Publics and China Harbour Engineering Company. Forty months later, the elevated roadways, which can be considered as twenty individual bridges separated by movement joints, were supported in the sky by some 94 columns.

The design of the viaduct was carried out by Arup Hong Kong who based the design of the pre-cast segmental viaducts on the use of 4m long segments. The design had to cope with complicated geometry and tight curves, and deal with typhoon effects on slender columns up to 70m high.

The 1,939 prefabricated segments cast in mainland China and delivered to Hong Kong by barge, were erected using the balanced cantilever construction method. The structure required the manufacture of specific tools for its construction. The “Fei Long” launching girder (Flying Dragon in Cantonese), 150 metres long and weighing 700 tons, was specially designed for this project and made it possible to install an average of three pairs of segments per shift, with a maximum of seven pairs of segments erected in a single day.

Pier slenderness required innovative approaches for temporary works design, which was carried out in Bouygues Travaux Publics Technical Department. A full 3D model, generated by Datums software, was shared between the Hong Kong and Paris teams for Geometry Control purposes as well as cantilever stability or external temporary pre-stress design.

The three main Challenges on the project were the height of the structure, the segment erection of the small radius loop and the schedule. Handover to the Highways Department was on time according to the contract requirements.