Wharf 6

Scope

The primary scope of work for the project is demolition and construction. Six breasting dolphins as well as walkways are to be demolished. An additional mooring dolphin located at Wharf 5 would also be demolished. Both structure and walkway piles are to be removed by vibro hammer. Second phase of the project is the construction four breasting dolphins and one mooring dolphin. Here the scope of work can be further broken down to installation of temporary staging, piling, construction of dolphin, installation of pre-cast walls, concreting works and installation of walkways.

Challenges

HSSE
Adapting to the new. Shell has raised the bar of their safety standards. Previously accepted practices such as worker to tie pipe clamps in water while wearing a life jacket is now no longer permitted. Comprehensive documentation and MS/RA are part of requirements. Besides critical and major activities, daily activities like refilling of diesel also require a MS/RA. This new change in standard meant that the project team was inadequately prepared at the start of the project.
Demolition
Due to stiff ground condition, the breasting dolphin piles could not be removed using the vibro hammer. While the walkway piles which has lesser soil penetration could be removed with ease. To remove the dolphins, a team of divers had to be mobilised to cut the dolphins at seabed level. As a result it now takes almost three times longer than planned. Each row of piles were cut and lifted. However the weight of the piles for the bigger dolphins exceeds the crane lifting capacity. Therefore it has to be repeated twice.
Logistics
Steel pipe piles are welded to 45m long at Penjuru yard. Due to space constraint only 5 to 6 piles can be welded at a time. Further limited by the crane capacity it is unable to lift the 45m pile. Hence the final weld joint has to be made on the material barge. As a result the delivered piles have to be consumed within the shortest period so that the material barge can be returned to Penjuru where the final joints are to be welded.