A4060, Merthyr Tydfil
The A4060 in Merthyr Tydfil links the A470 at Pentrebach with the Heads of the Valleys road (A465) in Dowlais.
The majority of the A4060 was constructed on a steep hill and is overlooked by the Ffos-y-Fran land reclamation scheme site on the south-bound side of the carriageway.
At the toe of a hill below the Ffos-y-Fran site lies a large drainage channel which runs adjacent to the road, measuring approximately 410m in length with a variable profile of 5.5 – 10 linear metres. The purpose of the channel is to manage surface runoff from the hillside and protect the A4060 from flooding and undermining.
Over the years, the channel had been remediated using poured concrete, cement-filled sandbags and concrete slab work. However, each had failed to some degree and the channel was in disrepair.
In order to prevent undermining of the embankment, it was decided that the channel should be excavated, graded and lined with Concrete Canvas® to provide a long-term protection solution.
The works were carried out on behalf of client South Wales Trunk Route Agent (SWTRA), with design specifications produced by consultants AECOM.
The channel profile was widened in some areas and groundworks carried out in such a way that the gradients of steeper areas were decreased in order to prevent overtopping.
Weather conditions were challenging throughout, causing concerns that the ground preparations could be washed away. To prevent this, the team prepared the channel as works progressed. Installation of the material itself was able to continue as CC is workable for up to two hours following hydration, whereas installation of traditional concretes would be disrupted.
The project was completed over a four-week period by a team of six, with 2,875m² of CC installed in total. The re-alignment, widening and lining of the channel will protect the A4060 from flooding and associated closures, which would otherwise cause significant delays and cost to an important trunk route.