AURS ROAD COASTAL DEVELOPMENT
More than 12,450 m³ of Leca® Lightweight Aggregate (LWA) was specified and installed as part of the Aurs Road infrastructure upgrade in East Renfrewshire, Scotland. The project forms a key element of a wider transformation of the route, converting what is currently a winding single carriageway into a safer, straighter road with a dedicated active travel corridor and a new waterside promenade overlooking Balgray Reservoir.
The scheme is being delivered by GRAHAM, with the project led by East Renfrewshire Council as part of a wider programme to improve connectivity, road safety and sustainable transport infrastructure in the area.
Project Context
Aurs Road runs directly along the earth embankment dam of Balgray Reservoir, which presented a significant structural and geotechnical constraint for the design team. Any widening of the road or addition of new infrastructure required careful management of loading to ensure the integrity and long-term stability of the dam structure.
To accommodate the new cycleway, footpath and promenade, the design incorporated a reinforced concrete retaining wall extending over 600 metres along the route. Ground conditions vary along the alignment, adding further complexity to the structural design.
FACTS
Amount of material: 12,450m3 of LECA LWA (10-20mm)
Interesting Fact: To create the additional width required for the cycleway and footpath, the design incorporated a reinforced concrete retaining wall extending over 600 metres along the route.
Delivery Method: Walking Floor
Main Contractor: GRAHAM
Design Team: STANTEC
Engineering Challenge for STANTEC
Because the works sit directly on the reservoir embankment, limiting the bearing pressure imposed on the dam was a critical design requirement. Excessive loads could increase the risk of settlement or affect the performance of the existing earth structure.
To address this, the structural design team at STANTEC investigated methods of reducing both vertical loads on the foundation and lateral pressures acting on the retaining wall. The use of a lightweight engineered backfill was identified as an effective solution.
Lightweight Engineering Solution
Leca® LWA was specified as the primary backfill material behind the retaining wall due to its significantly lower density compared with conventional granular fill. This allowed the design to substantially reduce loads transferred to the dam while maintaining the structural performance required for the new infrastructure.
The lightweight fill supports pedestrian and cycleway loading, with the retaining wall designed for a 5 kN/m² surcharge.
Key engineering advantages included:
- Reduced vertical loads on the dam embankment and retaining wall foundations
- Lower lateral earth pressures acting on the wall structure
- Improved stability across varying ground conditions along the 600 m alignment
- Consistent compaction and drainage performance
In total, over 12,450 m³ of Leca® LWA was delivered and installed for the formation and retaining wall backfill works.
Project Delivery and Funding
Construction of the scheme is being delivered by GRAHAM, managing the installation of the retaining wall, road realignment and active travel infrastructure along the reservoir edge.
The £22.68 million project, led by East Renfrewshire Council, is funded through multiple sources including:
- £12.72 million from the Glasgow City Region City Deal, comprising £5.5 million each from the UK Government and Scottish Government, plus £1.72 million from East Renfrewshire Council
- Additional funding from Transport Scotland through Sustrans’ Places for Everyone programme
- Support from the Scottish Government Bridge Fund
- Developer contributions from housing developments in the surrounding area
- Supporting Sustainable Infrastructure
The Aurs Road project highlights how lightweight engineered fill materials can play a critical role in infrastructure projects built on sensitive ground conditions, particularly where load reduction and long-term stability are key design drivers.
Once complete, the upgraded route will provide safer road infrastructure, improved walking and cycling connections, and a new public promenade with views across Balgray Reservoir, delivering both transport and placemaking benefits for the region.
The scheme is scheduled for completion in May 2026.
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