Fleming Road culvert: floating in a seal plate

The culvert under Fleming Road in Wan Chai had to be sealed at one end while it was still full of water, with no room for a crane inside.

We first surveyed the culvert and drew it section by section from CH0 to CH160, then designed the seal plate and a way to get it in:

1. Divers use floats to bring a lifting frame and a small working platform to the seal position.
2. The 500 kg plate is floated in on 200 kg air floats, towed over pulleys.
3. Air is let out of the floats on one side so the plate tilts upright.
4. A 1-tonne chain block on the frame lifts it onto its seat.