Extensive marine works are currently underway at the Pier Head in Liverpool, in front of the iconic Royal Liver Building where a new berthing facility is being built. NCE reports.
Marine works at Pier Head in Liverpool are now underway as part of the waterfront redevelopment. They include improvements for the Liverpool cruise liner and Isle of Man ferry berths. The century-old Princess Landing stage was replaced in the 1970s, but sank in 2006 after it was damaged by freak weather.
Contractor Balfour Beatty began the latest phase of work in April last year under an early contractor involvement contract to design and construct a new £7M Mersey Ferries landing stage.
Completion this year
Construction of the 64m long pontoon and 43m linkspans started in November 2010 and is due for completion towards the end of this year.
The project has required input from naval architecture specialists, dredging consultants, marine civil engineers and specialist plant suppliers to consider all aspects of the sensitive design for this famous location WM Plant Hire was involved with the salvage of the sunken landing stage in 2007. Last month its 65t long reach excavator fitted with specialist attachments was mobilised to clear any remaining parts of the original structure that conflict with the new pontoon. Hydrographic survey data has been used to find obstructions including sections of reinforced concrete in water which can be as deep as 13m at high tide.
The challenge has been for the machine operator to locate these using a computerised dig system providing real time information on the bucket position underwater.
Range of attachments
Fitted with a range of hydraulic attachments weighing up to 4t, the machine is able to tackle reinforced concrete by cutting the steel using a shear and crush the concrete with a pulveriser jaw.
Electronic sensors provide an underwater picture of the work tools, their orientation and position to known coordinates.
The excavator bucket is then fitted to clear the material and dredge the seabed to the new profile.
Piling work will follow the removal of the underwater obstacles. Marine civil engineers Commercial Marine & Piling (CMP), has the contract to install the massive tubular piles to anchor the new landing stage and to dredge the sea bed to ensure it is free from any other obstructions that could damage the floating structure at low tide.
Construction of the new pontoon is due to be completed in the next few months.