Castle Peak Road is one of the longest, and traditionally one of the most congested, roads in Hong Kong.
Halcrow’s involvement in two major projects at Castle Peak has been instrumental in improving life both for people who live alongside the road and for those who use it regularly.
The company was initially engaged, in joint venture, by the Hong Kong Highways Department, to design and supervise construction of a scheme to widen and upgrade one of the worst congested stretches of the road, between Area 2 and Ka Loon Tsuen. This 8.5km length of single carriageway was to be upgraded to dual carriageway standard, but the topography of the site made it an extremely complex and demanding task.
The road in this location is on steeply sloping sidelong ground leading to the sea, so the upgrade project involved constructing new cuttings and retaining walls, as well as many sections of new viaducts. A combination of this complex topography, the adjacent heavily trafficked road and existing property developments, villages and landmarks, made both design and construction a real challenge.
In all, the design includes 21 viaducts, 11 footbridges and over 4km of retaining walls.
Halcrow’s first task was to review design proposals, followed by detailed design, tendering and construction supervision. Our range of activities included highway design, stability design of steep cuttings, traffic and drainage impact assessment, ground investigation, water main design, slope design, bored pile wall design, viaduct design and footbridge design. We then supervised the construction contract.
This section of the Castle Peak Road Improvement was one of the first partnering projects the client had undertaken, so we put a lot of effort into seminars for staff to encourage co-operation and trust, and also into ensuring that the quality of design and construction set an example for future projects.
Our involvement in the Castle Peak Road improvements continued when we were appointed as a subconsultant on a contract to upgrade the next section of the road, from Ka Loon Tsuen and Siu Lam. The project was let as a design and build contract to Gammon Construction, whose designer Meinhardt Mouchel appointed Halcrow to design the road alignment and pavement.
It involved widening a 1.1km stretch of Castle Peak Road from single three-lane carriageway to dual two-lane, constructing a 1.0km section of new road - including an 800m long viaduct, reconstructing a 1.2km section of the road, and building new sea walls, slope stabilisation, landscaping, street lighting and drainage.
Two critical issues of this assignment were a very tight design and construction programme, and ensuring the scheme had minimal negative impact on the environment – particularly when it came to reclamation, tree felling and transplanting, and slope formation and excavation.