Stena VT4 Scour Protection Works, Belfast Harbour

Stena VT4 Scour Protection Works, Belfast Harbour

Contract Value: £1,000,000
Consulting Engineer: Doran Consulting
Engineer's Representative: Campbell Davis (028 9033 3443)
Client: McLaughlin & Harvey
Client's Representative: John Mariner (028 9034 2777)
Works Completion Date: April 2012

Scope of the Works:

- Mobilisation of a 24m x 12m Spudleg Barge with Hitachi EX650 Long Reach Excavator (70T machine with 25m reach). The barge was fitted out with a 100T capacity on-board Hopper Bin for the temporary storage of dredge material or scour protection material. Attendant shore-based plant mobilised for the offloading and re-handling of rock armour.

- The Main Contractor was responsible for the initial bulk dredging of the berth to accommodate the new Stena Superfast VII and VIII proposed for the new Stena ferry sailings between Belfast and the new Loch Ryan Port in Scotland.

- Following the initial bulk dredging works, Ashleigh Contracts undertook the final trimming works and attendance on the preparation of the seabed for the installation by divers of concrete scour protection mattresses along the full length of the quay and around the perimeter of a newly-formed dredge pocket for a vessel turning area at the seaward end of the VT4 berth.

- Scour protection adjacent the concrete mattresses along the main berth ocmprised the trimming out of a toe channel and infilling with rock armour up to 2T overlaying geotextile placed using divers.

- Scour protection in the new vessel turning area comprised the placement approx.. 30,000T of rock armour in layers up to 2m deep overlaying geotextile which was placed in advance by divers.

All scour protection works had to be undertaken whilst the VT4 berth was being used as a live berth for the ongoing Stena Belfast to Scotland Ro-Ro ferries and hence 24 hour, 7 days /week working had to be deployed with the maximum time available between ferry berthings to be approx. 2Hrs to 3Hrs up to 6No sailings per day being accommodated



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