Sai Ying Pun box culvert: bulkhead, joint sealing and grouting
A six-step method to isolate a seawall box culvert, clear it and seal its joints, with the bulkhead lowered at night by divers working inside.
- Year
- 2010 – 2011
- Location
- Sai Ying Pun, Hong Kong Island
- Status
- Completed
- Category
- Hydraulic
The box culvert at Sai Ying Pun had to be closed off from the sea, emptied and sealed, one unit at a time.
- Excavate to expose the roof slab of Unit 6.
- Install a steel bulkhead over the culvert mouth.
- Remove the sand and silt to a sediment tank.
- Seal the joints with polyurethane resin and 2 × 20 mm stainless strips on M12 anchors.
- Dewater through sediment and treatment tanks to the discharge point.
- Concrete.
The bulkhead went in overnight. During the day the gasketed plate was hung at +1.8 m and three chain-block anchors were fixed, after clearing 250 mm of marine growth from the culvert mouth. At night it was lowered over the opening while a diver inside tensioned the blocks, and the pumps were started once it sealed.
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