Night-time shot of Carney Construction project site with operatives working with Carney plant on a civil / groundworks project

SM4RT Motorway – M4 Structures

Project overview

Working for the BBV (Balfour Beatty Vinci) JV – Carney have completed the RC construction for 5 number overbridges on the live M4 motorway. The scope was further increased during the delivery of 2 further bridges, Utilities, Footpaths, Specialist Plant, Gantry bases, Culvert, Cast L-shapped Retaining walls and lift them in position & Scaffolding.

Key info

  • Start date: February 2020
  • Project completion date: 26th November 2020
  • Form of contract NEC: Option B
  • Total value: £3.2million+

Under a NEC contract Carney Construction have managed to reduce the programme duration by 6 weeks for the main structures construction. This has allowed the client to increase the scope by including further ancillary works increasing the value from the original £1.8 million to £3.2 million projected works.

Much of the increase in delivery was supported by other Carney divisions including the Scaffolding division approx. £775k+ and Plant division, providing vacuum excavators, concrete pumps, mobile cranage and safe access £290k+ and Groundworks/Utilities £145k+


1. Safety & Environment

During the development of the scheme Carneys proposed to use a 1.5t excavator with concrete percussive drill attachment to avoid the risk posed by HAV and maintained production rates for the works. This was presented to Highways England who were satisfied the controls were in place to protect the workforce from HAV and permitted the work activity to be commenced.

While the COVID-19 pandemic did come to bear on the project progress was maintained by increasing site resources, implementing segregations between the teams to provide working bubbles and tripling the site vans to ensure operatives could remain separate when out of works. Full additional compliance to site controls was implemented including onsite temperature checks, individual operative risk assessments, hand cleaning stations, rotation of breaks etc. works progress was improved upon with the additional resources and rotated shift patterns utilised.

Local engagement with nearby farm and learning centre was championed by Carney donating used / spare materials for construction of fencing and animal shelter, this has engaged the local businesses while assisting in reducing the carbon footprint of the site and improving recycling targets.

2. Quality

For this scheme the structures were awarded to two contractors, Carney Construction currently have been awarded all the further structural bridge packages due to out clients satisfaction with the workmanship, productivity and value brought to the project when comparing us with our competition.

By utilising our own shuttering systems and developing bespoke temporary works designs Carney Construction have been able to provide high levels of concrete finish requiring minimal post striking work, able to be completed within the same night road closure, critical to the safe delivery of the project.

Carney Construction site team have been recognised by their quality with important additions of bridge bearing installation and being present to provide supervision for bridge beam installations, this is key work items which required the highest level of accuracy when working.

3. Productivity

Early engagement with permanent works designs has helped avoid problems holding up progress onsite, Carney Construction have actively raised concerns with the TQ process and proposed solutions where possible.

In many of the structures Carney Construction have managed to decrease overall construction programme bringing both time and cost saving while maintaining high standards across the site. It is projected that the contract works have been delivered 6 weeks ahead of planned completion.

Conclusion & Summary

Carney have been praised for the workmanship of the site team allowing client engineering team to focus on programme and progress management. The client is happy to recommend Carney Construction on future works and is currently discussing future HS2 & M25 packages, summary of development:

  • Zero Harm achieved.
  • Full construction support available including design engagement, temporary works designs, methodology and construction simplification.
  • Vibration monitoring and innovative solutions to reduce risk.
  • Specialist plant able to provide peace of mind when working around critical services.
  • Co-ordinating site operations around COVID safe measures to remove delay and improve programme.

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