A large amount of uncharted, buried underground services were encountered during the works – many of which had previously been installed at an incorrect shallow depth. This included a variety of medium pressure gas mains, water mains, electricity supplies, street lighting cables, telecoms and Virgin fibre optic cables. To overcome this challenge, we worked closely with our client to chart the services, engage with the services providers and assist them to lower or divert the services. This also required us to extensively re-sequence our works to maintain schedule.

As work started on site, we also encountered an extensive reinforced 300mm depth concrete raft beneath the road surface covering the entire construction site. This unplanned work required us to break through the raft to excavate every hole on the project – taking 3-4 times longer than anticipated. To maintain the original schedule, we opened additional concurrent workfaces and deployed additional labour and specialist demolition plant.

With over 35,000 vehicles per day using this route, we planned the work to minimise disruption to road users. Civil construction was conducted during the daytime under temporary lane closures between 09.00 and 15.30 each day and surfacing works was conducted at night under full road closure with diversions. This not only allowed us to complete the work faster but avoided full road closures during the day and avoided congestion at peak traffic times.