Comprehensive roadway investigation in Bognor Regis must account for the complex coastal plain geology that defines this stretch of West Sussex. The town sits predominantly on Quaternary Brickearth and raised beach deposits overlying the Cretaceous Chalk, which is a critical factor for pavement design and long-term maintenance. These superficial deposits can be highly variable, often comprising soft silts and clays with pockets of sand and gravel, posing a significant risk of differential settlement. A robust ground model, developed through rigorous investigation, is the first step in de-risking any highway scheme, ensuring compliance with the Design Manual for Roads and Bridges (DMRB) and local West Sussex County Council adoption requirements.
Our methodology is strictly aligned with UK standards, deploying a phased approach that combines intrusive and non-intrusive techniques to BS 5930:2015+A1:2020 and Eurocode 7. We move beyond traditional trial pitting by utilising Cone Penetration Test (CPT) profiling to gain continuous, high-resolution data on the soft alluvial soils without disturbing the pavement structure. This is seamlessly integrated with In-Situ to determine the critical CBR values necessary for flexible pavement design. For granular sub-base and capping layers, we verify compaction compliance using the field density test (sand cone method), a definitive standard for earthworks specification in accordance with the Manual of Contract Documents for Highway Works (MCHW).
Typical projects in Bognor Regis range from realignment schemes along the A259 corridor to the structural design of foundations for new signalised junctions and pedestrian overbridges. The high water table in areas adjacent to the Aldingbourne Rife often requires a detailed assessment of buoyancy and scour potential. Our foundations design service specifically addresses these challenges, analysing pile friction within the chalk bedrock or designing shallow pads on the granular marine terraces. For carriageway reconstruction, we avoid a generic specification by providing a complete laboratory analysis of the subgrade, including grain size analysis (sieve + hydrometer) and Atterberg limits to accurately classify the shrink/swell potential of the cohesive Brickearth, a notorious local hazard.
The process concludes with a factual and interpretive report that serves as a geotechnical design certificate, not just a data dump. By combining our accredited laboratory testing with the field data, we deliver a clear parameter set for analytical pavement design, reducing over-engineering and aggregate import costs. The value lies in providing a single, integrated ground investigation package that satisfies both the earthworks and structural demands of a roadway project, ensuring durable infrastructure that stands up to the aggressive coastal environment of Bognor Regis.