National Highways has launched a 'Structures Moonshot' call for ideas to help identify 'three dimensional crack propagation in a half joint bridge samples'.

Through the industry leading research Structures Moonshot programme, National Highways has already trialled a wide range of non destructive testing (NDT) techniques, (Highways magazine July 2025 Pages 18-19), both established and emerging, to evaluate their effectiveness in assessing the condition of hidden critical bridge elements, including post tensioning systems and half joint details.

The national operator is now inviting expressions of interest and innovative ideas to support 'a live forensic investigation into crack propagation within a reinforced concrete half joint bridge element'. This work will use a full-scale sample taken from the previously decommissioned A14 Huntingdon Railway Viaduct. 

This latest call is not limited to traditional NDT methods. National Highways said it are equally interested in cross-disciplinary approaches, including civil engineering, materials science, geophysics, robotics, sensing technologies, or data-driven inspection methods.

If successful the techniques may inform future inspection strategies for half joint bridges more widely, National Highways said. 

In a statement, National Highways said it is looking for 'novel or emerging techniques that can help detect, image, or characterise internal concrete cracking at re-entrant corners, including (but not limited to):

  • Techniques capable of identifying crack presence, orientation, depth, or continuity.
  • Approaches suitable for near-surface or full-depth assessment, particularly from the soffit.
  • Methods that can operate on a real, reinforced concrete structure, rather than laboratory specimens.
  • Technologies that would benefit from validation through subsequent physical demolition.

Anyone with a technology, method, or idea that could help address this challenge is invited to make a submission outlining the principle of the technique, the type of cracking information it could provide and any relevant previous applications or trials.

Participants will have the chance to take part in a funded trial (for selected technologies), under a defined programme of learning and validation.

It also provides the rare opportunity for direct comparison of inspection outputs with physical evidence once the sample is dismantled, in a collaborative environment involving client, consultant and specialist partners.

The technical challenge

National Highways officials said: 'A key uncertainty for ageing half joint bridges is understanding how cracks initiate and propagate through re entrant corners, particularly through the depth of the section. While surface observations and conventional inspections provide partial insight, there remains a clear gap in our ability to:

  • Identify, characterise and validate internal cracking
  • Do so in a robust and repeatable manner
  • Assess cracking across the full width of a bridge.

The focus is on identifying cracking, not on the deterioration of reinforcement. Technologies that only infer cracking indirectly through reinforcement deterioration may be of limited value for this specific trial.

The closing date for submissions is 17 May - contact moonshot.comms@atkinsrealis.com.