| | Skanska Balfour Beatty Civil Engineering Joint Venture |
| | Essex, Bucks, Herts |
| | Jan 2009 |
| | Dec 2014 |
The Highways Agency engaged a consortium of Balfour Beatty, Skanska, Atkins and Egis to undertake the £580 million motorway widening contract.
The project increased capacity on the M25 between junctions 16 and 23 in Buckinghamshire and Hertfordshire, and Junction 27 and 30 in Essex. The carriageway was increased to four lanes in each direction.
A main project requirement was to keep three lanes open in each direction at all times; the construction sequence was planned to do just that.
The hard shoulder was used to maintain traffic flow. Concrete retaining walls were constructed over significant lengths, to allow the extra carriageways on each side to be constructed without further land acquisition.
Work was carried out twenty-four hours a day, seven days a week to meet the tight project timescales.
