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CIVIL ENGINEERING PROJECT

M606 Mill Carr Culvert

CECA Yorkshire and The Humber ‘Project of the Year’ Winner

Carnell successfully renovates a 160m twin pipe culvert beneath the M606 in West Yorkshire for National Highways, using innovative trenchless engineering techniques to restore a critical structure with minimal disruption.

Introduction

Corrosion of a twin pipe culvert under the M606 in West Yorkshire had compromised its structural integrity. Due to the location, length, construction and configuration, several contractors had declined National Highways’ attempts to renovate the ‘significant structure’ over the years, having found it too difficult to do. A collaborative approach by Carnell and trenchless specialists OnSite brought engineering solutions through ECI. This problem-solving approach continued during the construction phase, to successfully remediate the 160m long culvert with 1570mm diameter pipes. The scheme received praise from the local community and client which contributed to it winning the CECA Yorkshire & The Humber Project of the Year Award in 2025.

Early Contractor Involvement

ECI identified several challenges:

– Pipe length and circumference meant the liners would need UV curing. This technique can’t negotiate corners, so excavation of the bend was required.

– Corrosion of the corrugated steel pipes meant voids, while asbestos coated bolts couldn’t be cut.

– The inlet and outlet locations with nearby gas main and buried services required imaginative solutions to minimise the impact on the local community. 

Delivery

Carnell started the construction phase by undertaking enabling works, building a haul road, establishing a compound and boundary fencing. With temporary works designs by sister company AmcoGiffen, Carnell coordinated and supervised their implementation.

Innovative technologies, processes and techniques were used throughout the project:

To de-water the culvert, OnSite used their proprietary PortaDam system on the watercourse upstream, with flumes diverting the beck through the pipe not being worked on.

A 4.5m deep by 5 metre square excavation then needed to be created to access the pipe bend. A Movax side-grip piledriver was identified as the best solution to install the 9m tall sheet piles, a relatively new technique not used by Carnell before. This high-frequency, vibratory piler enabled the temporary earthwork support to be installed quietly and accurately, using a 35-tonne excavator.

The critical part of the scheme was the cured in place pipework (CiPP) remediation. The undersized (1350mm circumference) CiPP liners were delivered in a refrigerated truck, with the 100m lengths weighing 21 tonnes!

Onsite have the only tracked lining conveyor in the UK, meaning that despite the obstacles and challenging ground conditions, the liners were inserted smoothly via the deep excavation, and winched through from the inlet or outlet accordingly. The liners are a 16.4mm thick ‘jeans’ fabrication impregnated with gridfoil, an innovation necessary to prevent over-expansion, meaning it could be inflated and cured without being compressed against the existing culvert and being punctured of deformed by the bolts and corrugation.

Once the liner was cured using a UV lighting rig, foam concrete was injected between the liner and armco to fill the entire void in the anulus and provide structural integrity. Weholite pipe sections were lowered into the excavation with CiPP patches installed internally at the joints to create seamless pipe runs prior to the excavation being reinstated.

Adding Value

 

The project manager and Public Liaison Officer forged strong relationships with key stakeholders. Safety talks were given to Woodlands primary school and a new perimeter fence installed in return for using the playground as storage during the summer holidays. Road closures were agreed with a local distribution centre, Kirklees Council and Bradford MBC. Proactive and reactive communications were provided to customer including face to face meetings with vulnerable members of the community and a post-completion feedback session.

Social value activities were completed including provision of a defibrillator and a walk to school competition. Correspondence from each of the stakeholders above contributed to the Carnell project manager receiving an award from National Highways ‘for outstanding customer service’. A presentation titled Customer Engagement: Sharing Best Practice was subsequently given to the National Highways Yorkshire North East community.

Benefits

Safety
  • The scheme was safely completed without any RIDDOR reportable incidents or LTIs and had a Zero AFR.
  • Several uncharted ‘pot-ended’ cables were identified during excavations. A cable detection specialist was brought in to undertake detailed surveys.
  • Use of SafetyCam to improve driver behaviour on local roads reducing red light jumping, incursions and speeding.
Customer
  • A retired community police officer was recruited as Public Liaison Officer to engage with the local community.
  • Carnell’s project manager also received a National Highways Customer Service Award.
  • Customer risk assessment, comms plan and stakeholder mapping were undertaken.
  • Liaison with the school and local pub facilitated social impact.
Delivery
  • 2x 160m culverts remediated using 16.4mm thick liners impregnated with GridFoil.
  • Delivered well under the original budget to the 26-week programme.
  • Inspection Test Plans (ITPs) were created to document quality assurance and control.
  • Carbon reduction of 77t CO2e achieved by using solar generators and HVO fuel to power the compound and plant.
“The collaborative approach was the most impressive aspect. A team was created comprised of the client and all the suppliers, enabling up-front and honest discussions. This yielded results in terms of programme, pricing, delivery and community liaison. We are using the same team for Culvert 130, as we want those people back involved!”
Richard Burgess Project Manager, National Nighways