Critical Bridge Inspection Completed Without Highway Disruption

Client / Site: North Yorkshire County Council, River Derwent Crossing

Diver in the river near stone pillars of a bridge

Safety Performance:

  • 6 successful dives in challenging river conditions
  • Zero accidents, near misses, or incidents – perfect safety record
  • 3 proactive safety observations raised by our team
  • 2 RAMS improvements proposed to client and implemented
  • Compliance: Full adherence to ISO 9001, ISO 14001, ISO 45001, CDM Regulations, and Road Traffic Regulation Act 1984.

The Challenge

North Yorkshire County Council needed an urgent structural inspection of their 70-year-old River Derwent bridge – a critical highway link that couldn’t be closed for assessment.

The bridge’s underwater foundations presented multiple operational challenges:

  • Shallow caisson footings (concrete foundation chambers) partially exposed to turbulent river flow
  • Heavy siltation around pier bases restricting access and visibility
  • Constrained tidal windows limiting safe working periods
  • Active highway above requiring zero disruption to traffic flow
  • Short notice deployment demanding rapid mobilisation and execution

Any closure of this vital transport route would have significant economic and social impact on the local community.

Our Response

Dagger Diving deployed a specialist bridge inspection team with mobile equipment designed for rapid deployment in challenging riverine conditions.

Strategic Setup – We positioned a road-transportable dive control unit with modular equipment staged directly from the riverbank, eliminating the need for marine vessels in the shallow, fast-flowing river.

Engineered Access – Working with temporary works designers, we installed scaffolded dive platforms suspended beneath the bridge structure. This provided safe, stable working platforms whilst maintaining full highway access above.

Advanced Inspection Technology – Our surface-supplied divers used high-definition helmet cameras for real-time visual documentation, ultrasonic thickness gauges to measure concrete integrity, and pit gauges to assess any structural degradation.

Precision Planning – We conducted detailed hydrology reviews and time-critical dive planning to work safely within tidal flow patterns and challenging riverbed conditions.

Safety Protocols – All operations followed confined space procedures where required, with continuous gas monitoring and validated emergency egress plans ensuring diver safety in the restricted underwater environment.

The Outcome

Mission accomplished – comprehensive inspection delivered ahead of schedule with zero highway disruption.

Complete structural assessment results:

  • All six piers and four abutments fully mapped and assessed
  • 12 structural anomalies identified – none classified as critical
  • 2-day operation window – completed faster than scheduled
  • Maintenance deferral approved – reinforcement work scheduled for Q3 2025
  • Highway kept operational throughout entire inspection period

Our rapid deployment and precision survey techniques enabled North Yorkshire County Council to maintain this vital transport route whilst fulfilling their statutory bridge inspection duties.

Project delivered ensuring public safety and infrastructure compliance with zero operational disruption.