A new 1.3km road widening scheme is currently underway along the A487 in Wales.
Located just south of Machynlleth, the A487 Glandyfi Improvement project has been designed to widen the stretch of road in order to significantly improve driving conditions for motorists. It is the first time a scheme like this has taken place on the A487 and will allow the road to reach the national speed limit – which, due to the limited width of the existing road, has previously proved unfeasible.
The project is being implemented between the River Dyfi, the local railway track and an existing hillside.
The £10m scheme began in February 2011 and has been funded by the Welsh Assembly Government. Designed by Parsons Brinkerhoff, the project is being carried out by main contractor Carillon Engineering and managed by EC Harris and Gifford.
Work so far has included the removal of approximately 80,000km of rock from the surrounding area. This has involved a rock cutting of 15m high by 500m in length, with the implementation of reinforced concrete rock anchors to support the remaining structure. Interestingly, the rock cutting is completely clad in stone and therefore has the appearance of a large dry stone wall.
One of the main materials used on the scheme is masonry facing for the retaining walls and structures. Structural backfill and subbase – a layer of aggregate material that is laid upon the existing layer of the road – has also been used.
A second, smaller rock cutting is scheduled to take place in 2012, whilst a substantial effort has been made to recover most of the materials from the excavation in order for them to be reused.
Carillion Civil Engineering Contract Manager, Julian Wilson, said:
“Technically when you excavate rock it is waste material, but by using the WRAP protocol and working alongside the Environment Agency we have been able to reuse the rock at deposition locations near to the scheme.
“We donated some of the rock to the local RSPB reserve, which has helped with some of the reserve’s upgrades during its centenary year, and we also assisted a few local landowners.
“These landowners have had planning approval for ground improvements in their farm yards, so we’re trying to keep all of the material local.”
He added: “The result of this is that none of the rock excavated during the project has been sent to landfill.
“This has proved beneficial to both us and the local area as it would have taken a great deal of time and effort to transport the material to the nearest landfill site.”
As the A487 is a very narrow road and fragmented rock has at times proved difficult to break, all work conducted so far has been linked to traffic management. As a result, the widening project can only be developed in certain phases. However, work so far has remained on schedule.
Julian said: “Carillion Civil Engineering has also come up with a number of value engineering initiatives whilst working on the road’s development.
“This has included amending designs to save the Welsh Assembly Government some money on the project, which is always welcomed when undertaking a development like this.”
The A487 Glandyfi Improvement project is currently around 50% complete. The remaining structural work is to take place throughout early 2012, including the creation of three new 100m-long retaining walls against the railway. The construction of smaller retaining walls will follow, along with some finishes on the highway.
Work is scheduled to be completed in July 2012.