Investigation in Bognor Regis

Ground investigation in Bognor Regis must account for the town’s complex geological setting, including the London Clay Formation, superficial Brickearth deposits, and localised chalk solution features. A robust site characterisation programme is essential to comply with British Standards, particularly BS 5930 for intrusive works and BS EN 1997-2 for geotechnical design. A focused CPT test can rapidly delineate soft clay layers and potential dissolution hollows, providing continuous stratigraphic data where traditional boreholes alone may miss critical variability.

This investigative phase supports residential developments on the coastal plain, commercial builds near the town centre, and infrastructure projects requiring precise bearing capacity and settlement analyses. Integrating cone penetration testing with laboratory classification and environmental sampling delivers a reliable ground model for foundation design. The resulting factual and interpretive reports directly inform safe, cost-effective construction in an area where variable ground conditions frequently dictate engineering solutions.

Technical parameters

Parameter	Typical value
Design standard	BS EN 1997-1, BS 8081:2015
Anchor type	Active (prestressed) / Passive (deadman, soil nail)
Typical bond length in Bracklesham Beds	4.0 m – 8.5 m
Tendon specification	Dywidag bar or 7-wire strand (BS 5896)
Corrosion protection class	Class I (permanent) / Class II (temporary)
Proof load test acceptance	1.25 x working load (min 95% theoretical elastic extension)
Free length design	> 5.0 m or beyond critical slip surface
Creep rate limit	< 2 mm per log cycle of time during sustained load test

Related technical services

Prestressed Active Anchor Design

For retaining walls and basement slabs requiring immediate load transfer. We calculate the lock-off load, free length, and fixed anchor length using the cone method and local shear strength parameters. Each design includes a detailed stressing sequence and acceptance criteria per BS 8081.

Passive Anchor and Soil Nail Systems

For slope stabilisation and temporary excavations in the Bognor Regis area. We design self-drilling hollow bar anchors for collapsing ground conditions typical of the Wittering Formation, with pull-out capacity verified through on-site suitability testing.

Relevant standards

BS EN 1997-1:2004 (Eurocode 7: Geotechnical design), BS 8081:2015 (Code of practice for grouted anchors), BS EN 1537:2013 (Execution of special geotechnical works—Ground anchors)

Common questions

What is the typical cost range for an anchor design package in Bognor Regis?

For a standalone anchor design package covering a typical retaining wall or excavation support in Bognor Regis, the fee ranges from £820 for a straightforward temporary works design to £3,050 for a comprehensive permanent anchor scheme with corrosion protection Class I, finite element verification, and full construction-phase support. The final figure depends on the number of anchor rows, the complexity of the ground profile, and whether proof load testing supervision is included.

How do you determine whether an active or passive anchor system is more suitable for my site?

The decision hinges on allowable deformation. If the structure behind the anchor can tolerate virtually no movement—say, an existing building facade within Bognor Regis town centre—we specify an active anchor prestressed to 80–100% of the working load. Passive anchors are acceptable where some millimetres of displacement are permissible before the anchor engages, such as in temporary open-cut excavations or slope regrading projects. We assess the serviceability limit state and the proximity of sensitive structures to make the final recommendation.

What testing do you require to validate an anchor design?

BS 8081 mandates three types: suitability tests on sacrificial anchors before production drilling (up to 1.5 x working load), proof load tests on every production anchor (1.25 x working load), and a subset of extended creep tests where the load is held for up to 24 hours to confirm stable behaviour. In Bognor Regis, we typically recommend creep testing on at least 5% of permanent anchors due to the time-dependent deformation properties of the Lambeth Group clays.

Investigation in Bognor Regis

Available services

CPT (Cone Penetration Test)

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