CONCRETE COASTAL defences installed on Scarborough Headland last year as part of an ongoing £33M project have begun to crack, council officials have confirmed.
An urgent investigation has been launched to determine why the specially designed concrete Accropodes, used to protect the coastline instead of traditional rock armour, have begun to break up only months after being installed.
Work on the coastal defence project began in June 2002. It involves installation of hard coastal defences and a 1m high concrete wave return wall. The wall has been strongly opposed by the local public (NCE 5 May 2003).
Client Scarborough Borough Council has already seen the cost of the project rise from an original £24M estimate. It insists that the cost of this latest problem will be paid by the designer or contractor - depending on who is at fault.
'We will now have to see what the experts tell us before deciding on the next steps, ' said council chief executive John Trebble.
'It is already clear that the cracked Accropodes will have to be replaced.'
Contractor Edmund Nuttall, manufactured the precast units in Sunderland Docks, under a licence from French designer Sogreah (NCE 20 February 2003).
However, this week both Nuttall and scheme designer High Point Rendel refused to comment on the cracking.
Hydraulic experts said this week that it was unusual for this type of structure to fail so soon after installation. At Scarborough, each unit weighs 15t and is manufactured from a class IIIA concrete mix - ordinary Portland cement with 50% ground granulated blastfurnace slag.
The Accropodes' unusual shape makes them effective at dissipating wave energy and enables them to be built on a steeper gradient, therefore requiring a smaller footprint.
The council would not speculate on how long the investigation would take but it is understood that the cracked and broken units will have to be replaced before winter to avoid further damage to the defences.