CLIENT
Lovell Partnership
SCOPE OF WORKS
PROJECT BRIEF
Roger Bullivant Limited (RBL) were appointed by Lovell Partnerships to deliver a foundation solution for two phases of the Llanwern Steel Works redevelopment in South Wales. The site, located on the former coke ovens of the steelworks, presented challenging ground conditions due to its remediation history and compaction methods.
RBL’s challenge was to engineer a piling system that could withstand the tough upper layers, minimise environmental disruption, and accelerate the build programme to meet the client’s delivery targets.
KEY ISSUES
Contaminated Ground Profile: The site featured a crust of slag fill overlying very soft organic silty clay, raising concerns around spoil management and groundwater pollution.
Environmental Sensitivity: Proximity to the Gwent Levels, known for their historic watercourses and biodiversity, required careful consideration to avoid polluting underlying aquifers.
Ground Penetration Challenges: A piling technique was needed that could reliably penetrate the dense upper layers without breakages or excessive wear.
Noise Constraints: With occupied properties nearby, noise mitigation was a key consideration in rig selection.
SOLUTION
- Precast Pile Selection: RBL opted for 250mm square Driven Precast Concrete Piles to ensure reliable penetration through the tough slag layer.
- Displacement Technique: Precast piles were chosen for their displacement properties, eliminating spoil generation and avoiding the need for contaminated material removal.
- Groundwater Protection: Precast piles were driven to prevent plugging and minimise material transfer to the pile tip, safeguarding the sensitive watercourses below.
- Noise Reduction: RBL deployed ‘quiet hammer’ rigs with shrouded hammers and vertical exhaust systems to reduce noise emissions.
- Heave Design: The expansive slag fill posed a heave risk. RBL designed reinforced piles to resist uplift forces and secured NHBC approval for a bespoke heave solution, reducing reliance on traditional measures.
- Precast Foundation System: A fully precast foundation system was designed in-house, including pile layouts, beam layouts and typical sections. This approach reduced site deliveries, excavation, and insitu works, accelerating the build programme.
- Programme Efficiency: With minimal insitu work required, the precast system enabled early installation and handover of plots, supporting Lovell’s need for rapid build progression in a commuter-friendly location near the M4/M5 corridor.
- RBL’s innovative approach delivered a high-performance, low-impact foundation solution tailored to the unique challenges of the Llanwern site. Once complete, the project will have seen the installation of over 3,300 piles and 14,100 linear metres of beam across 500 residential plots, demonstrating the efficiency and sustainability of precast systems in complex ground conditions.
