A465: Ground Engineering Challenges and Successful Collaboration in the ‘Heads of the Valleys’, Abergele

4 February, 2016 | 18:00 - 20:00

Working in partnership to deliver section 3 of the A465 upgrade.
Working in partnership to deliver section 3 of the A465 upgrade.

About this event

Speakers: Kyla Nunn and Mark Cooper, Arup

The original A465 Heads of the Valleys road was constructed as a three lane highway. Sections of the route have since been widened to dual two lane, with construction of Section 3 – Brynmawr to Tredegar recently constructed by Carillion. The improvement works for Section 3 cover 7.3km of road, 5km of which comprise a new offline section of dual carriageway. The scheme was promoted by Welsh Government, partly funded by the EU and delivered as an ECI Design and Build contract valued at £120m.

The design and build team faced significant ground engineering challenges. These included dealing with a wide range of coal and ironstone mining features inherited from the site's industrial past; the design of a number of watercourse crossings which required a range of solutions; and maintaining no offsite disposal or import of fill materials. Solutions included design of an 18m span precast arch within a 30m high embankment – as an alternative to a viaduct.

Along the online widening sections various forms of retaining structures were adopted. As the scheme progressed and actual ground conditions were verified, design solutions were optimised. The successful integration of design and buildability generated real benefits, with innovative and cost effective solutions.

This presentation will provide an overview of the ground engineering aspects, highlighting the challenges addressed, and outline how optimum solutions have been reached. Emphasis will be put on the value of collecting and disseminating information during the works to refine the design, supported by close collaboration between members of the project team.

Refreshments available.