Hong Kong Link Road
Hong Kong Link Road (HKLR), a dual 3-lane carriageway, is approximately 12 kilometres connecting the Main Bridge and the Hong Kong Port. It comprises land and marine viaducts about 9.4km in length, a 1km tunnel and a 1.6km road section. Taking account of the complex site conditions, the contractor was required to cast about 5,700 large-sized precast deck segments within a tight construction programme which is about 40 months, and to adopt various construction plant and methods to erect the precast deck segments.
As regards the construction of the Scenic Hill Tunnel, four different construction methods were adopted to cater for the different ground conditions and topographical constraints ：
The most complex and arduous among the tunnel works was the box jacking operation carried out underneath the Airport Express Line (AEL). This method was adopted for the first time in Hong Kong for constructing a vehicular tunnel. To minimise impact on the AEL, the ground underneath had to be strengthened and strengthening works took one year to complete. The box jacking operation involved casting tunnel box segments in a deep and narrow shaft, excavation at the leading face of the box segments, and pushing box segments forward one by one by means of hydraulic jacks underneath the AEL. A computerised system with a high degree of precision and stringent techniques were required to synchronize movements of all the hydraulic jacks in pushing the gigantic box segments.
One of the main challenges of the HKLR was building a viaduct with a section running over the ecologically-sensitive Sha Lo Wan headland. Apart from the need to observe tight airport height restrictions due to the close proximity to the international airport, it was also necessary to avoid disturbing the land of high conservation value in the vicinity of the Sha Lo Wan archaeological site. The engineering team overcame the difficulties by making use of a massive straddle carrier to construct long-span viaduct 180m in length, currently the longest dual 3-lane prestressed precast concrete bridge span in Hong Kong. The design minimised the visual and environmental impact of the viaduct and as a result, not only is the structure not a blot on the landscape, on the contrary, it has become a feature of the area complementing the natural scenery of North Lantau.
