North and Mid Wales Trunk Agent (NMWTRA) and partners Alun Griffiths Ltd, DYWIDAG and Ymgynghoriaeth Gwynedd Consultancy (YGC) have won the 2022 ICE Wales Cymru Awards, Innovation award for a project to improve the A494 retaining wall at Llanycil, Bala.
The ICE Innovation Award recognises and celebrates a project that demonstrated exceptional innovative solutions to a particularly difficult restorative renovation project. The awards were given in a gala dinner at the Principality Stadium, Cardiff on Friday 30 September.
The A494 trunk road runs along the north-west bank of Llyn Tegid, and A494 is one of the busiest trunk roads in Wales. A long section was found to be unstable, with the road and its foundation creeping slowly towards the steep slope of the lake shore.
An innovative solution was found, incorporating a reinforced concrete king post (isolated steel columns) retaining wall supported by 36 ground anchors, 12 of which are smart anchors.
Using a unique force measurement sensor, the smart anchors can be monitored remotely with real time data being transmitted to a cloud-based system, permitting continuous surveillance of the asset’s performance. The data can be used to verify design predictions, improve modelling quality and provide insights for more tailored design solutions.
Clive Bayley, Procurement and Contract Manager for NMWTRA said;
“Our primary concern was the integrity of the vehicle restraint system; temporary traffic lights were installed to close the southbound lane. Due to the importance of the A494, we were keen to identify a permanent solution that would allow the re-opening of the road as early as possible.”
On behalf of the Welsh Government the North and Mid Wales Trunk Road Agency (NMWTRA) commissioned Alun Griffiths (Contractors) Ltd under an ECI contract to develop a solution. Working with Ymgynghoriaeth Gwynedd Consultancy (YGC) and DYWIDAG, several options were considered for the remediation of the embankment, with the preferred solution comprising a restrained/anchored reinforced concrete pile cap/retaining wall over a length of approximately 75m, with anchor piles spaced at 2m centres and embedded into the bedrock. The vehicle restraint system and pedestrian barrier were to be supported by the structure with both the highway and footpath regraded and resurfaced.”
Regional Director for Alun Griffiths, Owain Thomas said;
“The proposed solution would improve the factor of safety of the embankment, reducing any ground movement and resultant cracking in the highway and footpath, and delivering a 120-year design life.”
David Cooil, Head of Service, The North and Mid Wales Trunk Road Agent said:
“This part of the network is crucial to tourism and supporting local economies. We’re delighted that by investing in innovative technologies we’re now able to monitor the site 24/7. This allows us to identify minor issues before they become major problems and minimises disruption to local communities.
We feel proud to be involved in a project that will improve resilience on this part of the network for many years to come and would like to thank all our partners for their hard work throughout.”
More information about the award here: Innovation Celebrated At ICE Wales Cymru Awards | Institution of Civil Engineers (ICE)