The prefabricated double-arch steel bridge for the Cross Bay Link, Tseung Kwan O, arrived in Hong Kong on February 16 and was completely erected on the bridge piers on February 26, the Civil Engineering & Development Department announced. Upon completion, it will be the longest span and heaviest steel arch bridge in the city. The Cross Bay Link is about 1.8 km long, of which 1 km is a marine viaduct composed of several sizeable steel and concrete members. With a length of 200m and a weight of about 10,000 tonnes, the double-arch steel bridge was constructed with high-strength steel and is an integral part of the marine viaduct.
The steel bridge components are prefabricated in Nantong, near Shanghai, for delivery to Hong Kong in batches. The delivery vessel left Nantong on February 9 and entered Junk Bay in the morning of February 16. Spanning across Junk Bay, the Cross Bay Link will connect the southeastern areas of Tseung Kwan O with the Tseung Kwan O - Lam Tin Tunnel and provide linkage to Tiu Keng Leng and Tseung Kwan O town centre.
The Civil Engineering & Development Department said this is the first time the “float-over method” has been applied for bridge construction in Hong Kong. As the double-arch steel bridge weighs over 10,000 tonnes, the project team adopted the “float-over method” and took into account the tidal conditions when erecting it. The entire process lasted about five hours, starting from 7am until close to noon. At about 7am on February 26, the semi-submersible barge loaded with the double-arch steel bridge moved in between the bridge piers during the high tide window.
After precise positioning of the double-arch steel bridge, the barge pumped in 27,000 cubic metres of seawater for ballast, correspondingly lowering the barge by 1m for the double-arch steel bridge to touch down onto the piers. The about 1.8 km Cross Bay Link in Tseung Kwan O, comprising a 1 km marine viaduct, is scheduled for completion in 2022.