Zhuhai: pulling a 550 m cable-duct bundle under a river
A 550 m bundle of seven HDPE ducts, ballasted with concrete weights, was pulled across a riverbed through steel sleeves in the levees and jetted in.
- Year
- 2009
- Location
- Zhuhai, Guangdong
- Status
- Completed
- Category
- Underwater & marine
To carry cables under a river in Zhuhai, we built the ducts into a single bundle and pulled it across in one piece.
- The bundle: seven Ø250 × 12 mm HDPE ducts plus two Ø80 mm ducts, 550 m long, 42.5 tonnes in air but with about 162 tonnes of buoyancy.
- Ballast: 76 to 80 concrete weights of 2.1 tonnes each, at 6.8–7.2 m spacing, so it would sink and stay down.
- The pull: calculated at 8.2 tonnes underwater, through a Ø1.2 m steel sleeve at each levee, using a 25–30 tonne crane, a 5–10 tonne winch and sheaves.
- Burial: jetted into a pre-dug trench. Two trench options were compared by dredging volume.
Drawings
