Project review drives down costs
The Works required an economic and robust design to extend the usable quay side facilities in front of Venture Quays from 1500m² to 8500m².
This was achieved by the demolition of the existing apron and suspended slip way and establishing an area of reclamation impounded by a rock revetment and sheet piled ‘quay’ with boat hoist dock and pontoons, suspended relieving deck and new running surface for the enlarged apron.
Through review of specifications, available information and risk register review the project team were able to drive the costs down to an agreed figure. An early instruction to carry out site soil investigation helped provide a clearer picture of ground conditions. From this the designers were able to review the loads that the sub strata might take. This enabled pile and geotextile requirements to be accurately determined.
To develop the site it was necessary to breakout and crush the original apron and slipway. The existing slipway was demolished along with the breaking out of the existing apron slabs. All concrete was crushed and stockpiled on site yielding over 1500m³ of suitable fill.
A total of 41 raking tube piles were driven to support the relieving platform together with 16 similar vertical piles for the crane support deck. There was a further requirement for 12 piles for the hoist dock structure. The landward piles were driven using Mackley’s 70-tonne crane on a spud leg dumb barge, whilst the seaward piles were driven using a similar crane working from the land. A further 9 pontoon piles were driven by the floating plant to provide fixings for the 5metre wide pontoons. An arc of 26 toe piles were installed to retain the rock revetment using Mackley’s self propelled crane barge DB110.
An RC Boat Hoist lift-out facility was installed with the facility to accommodate 4.5m draft. The boat lift brings the latest technology to the Solent. The hoist is eco friendly and one of the fastest available reducing lift times to one third of conventional methods yet the equipment weighs half as much with twice the capacity.
Pontoons for berthing comprised of 5-metre wide concrete units supplied by Intermarine Ltd.