Aarsleff assists the Tywyn Coastal Defence Scheme
Aarsleff Piling
groyne piling
Aarsleff has provided groyne piling services for repair works to the sea defences along the Tywyn Coast, following years of extreme weather conditions causing extensive damage.
Severe storms over the past 100 years have damaged the sea defences along the coastal frontage of Tywyn on the west Wales coast of Cardigan Bay.
To prevent further erosion and damage, Gwynedd Council has started on an extensive repair project, which will reduce overtopping of the seawall and improve access and amenity of the beach for the local community, visitors and tourists.
A new rock armoured breakwater will be built, together with new beach material and new rock groynes and rock revetment protection.
In addition, there will be repairs to the slipway and access steps, refurbishment and improvements to the promenade and replacement of the existing dilapidated timber groynes, along the entire length of the beach frontage, with new ones added.
Many of the timber groynes are in a very poor state and are obstructing and preventing access along the beach.
The Tywyn Coastal Defence Scheme is being funded by the Welsh Assembly Government and the European Regional Development Fund.
Consulting engineer Atkins has designed the scheme for Gwynedd Council.
Atkins is also supervising the Tywyn project's construction by main contractor Jones Bros Ruthin (Civil Engineering).
Jones Bros went out to open tender for the groyne piling and Aarsleff Piling was successful with its submission.
Aarsleff had previously worked for Jones Bros installing piles for the Tullo wind farm in Scotland.
The specialist piling contractor had also installed all the timber groyne piles on the smaller, but similar Atkins designed scheme at nearby Aberaeron.
Aarsleff, using one of its Banut 700 self erecting piling rigs and working between the tides, installed the 5m long piles up to 3.5m into the beach sand.
The new groynes are spaced 50m apart along the beach and each row of groyne piles was driven in a straight line at 2.5m centres down the beach to a +/-50mm position tolerance.
The top levels of the piles gradually reduce towards the sea with the outermost piles upstanding by about 1.5m.
Aarsleff had to drive almost 400 greenheart piles and installed them at an average rate 30 per cent faster than its contract estimate.
On completion of the piling for each groyne, Jones Bros followed on behind with a team bolting on new greenheart waling bars and planks to the faces of the timber piles.
Jones Bros also has to build two new rock groynes, place some rock revetment and rebuild the slipway and access steps, including the concrete steps along the length of the promenade.
In addition about 15,000t of sand and gravel has to be placed as beach replenishment in the area between the new main breakwater and sea wall, prior to Jones Bros completing the Tywyn sea defence scheme on schedule in September 2010.
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