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Wed August 10 2022

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Piling completes on environmentally sensitive coastal project

29 Jul Marine piling works on the Welsh coastline facilitate construction of new leisure facilities as part of a coastal erosion-focused project.

Specialist contractor Sheet Piling (UK), working with Alun Griffiths Contractors and client, Colwyn Council, has completed the marine piling works for a new leisure facility in Old Colwyn, Wales.

Safeguarding leisure and lifestyle benefits has been at the heart of the works undertaken in Old Colwyn, which have been funded through the Welsh Government’s Resilient Roads Fund and undertaken to protect a National Cycle Network route, as well as the main sewer for Old Colwyn, the A55 and various railway bridges.

Having moved 40,000 tonnes of rock from North Wales quarries, to create a new rock barrier that protects the base of the Victorian sea wall from the impacts of rough seas and high tides, Alun Griffiths Contractors instructed Sheet Piling UK to take charge of two other aspects of the project. This was the creation of a new fishing platform and improved access to the beach over the existing rock groynes.

The new fishing platform, located at Splash Point by the Old Colwyn Arches, is intended to be a real asset for the fishing enthusiasts who visit for a spot of conger eel, mackerel, whiting or small codling fishing.

To create this new elevated facility, Sheet Piling UK installed ten raking piles and four vertical piles, all piles being tubular marine piles, 22.5m long, 610mm in diameter and with a wall thickness of 25mm. Each has had to be installed on the existing beach, working around tide times, and installation has required a bespoke approach, devised by Sheet Piling UK to match this project’s requirements.

This has been the modification of a conventional land-based piling trestle, in such a way as to deliver sufficient stability and capacity to support the tubular piles, once these were pitched into the trestle and whilst being driven in. The trestle was fitted with a rotating swivel guide, to accommodate the raking piles, and was lifted into each pile position using a 300Te crawler crane, positioned on the existing promenade.

Piles were then driven, initially using a PVE 38M vibratory hammer and then, during a final drive to level, by a BSP CX85 impact hammer.

Access to the beach, where this work took place, was provided by a tracked mobile elevated work platform, supported by the promenade-based crawler crane.

Better beach access has also been created. Sheet Piling UK has installed a series of sheet piles, to form the basis of new access steps leading from the promenade to the beach and traversing rocky groynes.

These steps are in two locations and have been formed using Arcelor Mittal AZ 28-700 sheet piles. The stiff clay in the positions in which they were required, meant the use of a pre-auguring technique, to loosen the ground a little before installation.  This was done using an excavator piling rig, with a Movax side-grip hammer.

A pre-cast concrete decorative effect will be positioned over both the steps and some new wall sections along the front, this having a special textured surface that helps promote marine wildlife habitats.

Sheet Piling (UK) managing director, Andrew Cotton, said: “It is essential to protect Victorian promenades and infrastructure in many of the UK’s traditional seaside resorts, to ensure that their benefits can be enjoyed by future generations. We are delighted to be able to use our sheet piling expertise within a project doing just that, and are pleased to know we are creating new leisure opportunities for those wishing to fully enjoy the Colwyn stretch of coastline.”

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