Laing O’Rourke/Dredging International JV are the main contractors for building the new London Gateway Port. The project of redeveloping the Sierra Jetty, Shellhaven, included a pile wall protecting a deep water berthing pocket for large tankers. The pile wall was leaking solids and creating voids behind the wall, so had to be surveyed to identify problem areas to rectify to approved standards.
Work was made more difficult by strong currents, zero visibility, embargoes on spud legs or anchors near the pile wall and the difficulty of working in close proximity to a working oil terminal. There were no local facilities for mooring or land access nearby.
UMC deployed teams of experienced inspection divers, tugs and barges and established a base at a local port to provide a self-contained work platform that could easily be demounted for tanker arrivals. This included provision of a fast crew transfer vessel for rapid deployment and emergency evacuation.
The divers performed a finger tip survey of over 300 piles at a maximum depth of 19m, working tides around the clock to maximise diving intervals and correctly identifying true orientation of piles, with defects classified into repair categories.
The client’s designer specified cemetitous repair methods to be used. UMC designed repair methods for defect categories using the latest materials, obtaining client approval.
Samples of the repair were taken at approved intervals and submitted to the client for testing. During operations the client deployed inspection divers from Royal Haskoning to monitor progress, with very favourable reports.