Wan Chai Reclamation Phase 1 & 3

In 2010 we installed seawall blocks and caissons for Section C2 of the Wan Chai Central Harbourfront Development.

In 2016 we returned for Section C3 to install temporary water diversion pipes through the box culvert bays, with steel bulkheads at Bays 7 and 8, and to remove them again when they were no longer needed.

Client for both stages: Civil Engineering and Development Department (CEDD).

More work in Section C3 (2016 – 2017)

The C3 works went on beyond the diversion pipes. We designed the water-stop and flow-deflector frames for the new cooling-water outfall pipe and culvert, a stop gate for Bay 19 (2017), the grouting arrangement at Bay 13, the steel formwork for the culvert walls, and the works for items 1 to 5 of culvert K (July 2017).

From the drawings

Cross-harbour water mains (2010–2011). For the new DN1000 steel mains across the harbour, we designed and placed the steel formwork for the underwater thrust blocks at the bends, with the invert down to −24.15 mPD. The formwork was lowered by derrick barge and levelled by divers, the gaps around the pipes sealed, and concrete placed by tremie from a hopper on a steel platform hung from the seawall, in pours of about 198 m³ and 150 m³.

Seawall and piles. We laid 6–8 tonne seawall blocks from −12 to −8 PD on a steel setting frame, cut 30 sheet piles underwater at −10 mPD, and cut Ø2.5 m steel-cased piles level at −10 mPD to expose the couplers, with a precast caisson (110 tonnes buoyancy) as the dry alternative.

C3 culvert (2017–2019). Inside the box culvert we fitted and later removed temporary diversion pipes of Ø2,500, Ø2,300 and Ø1,500 mm, behind a wall of about 9,000 sandbags. Divers made level cuts on 12 gate plates and 5 pile tubes and welded the pipe seats underwater. On removal the Ø2,500 pipes came out in 26 cut sections and the Ø1,500 in 9.