Ecocrib M6 J16-19, Knutsford to Crewe

The Challenge

In 2015 Kier was awarded the £233 million project to build Cheshire’s first smart motorway to help keep traffic flowing between J16 (Crewe) – and J19 (Knutsford), this included 40 Miles of extra lanes, 21 overhead gantries, 18 emergency bays and 258 electronic signs. Hundreds of metres of retaining walls were needed to allow clearance for the emergency refuge areas (ERA’s) and the overhead gantries to be built within the highway boundaries. “As infrastructures had a major impact on the M6 J16-19 critical path a cost-effective solution was needed to reduce the overall time of installation.” A durable, robust, economical, and sustainable retaining wall solution with a British Board of Agreement (BBA) Highway Authorities Product Approval Scheme (HAPAS) certificate was required to satisfy the Highways Agency.

The Solution

Several EcoCrib mass gravity retaining walls now support the embankments along the M6 J16-J19 to provide clearance for many of the ERA’s and Gantry Bases. Designed, supplied, and installed by PC Construction. Awarded a BBA HAPAS certificate in 2012 with a design life in excess of 120 years, Ecocrib is structurally robust yet the most highly sustainable retaining solution currently available for highway applications. It was the only retaining option that didn’t need heavy lifting equipment to complete the job which made it the safer option. It also allows the installation to be quicker and cheaper than the other options available. Ian Potts quoted on behalf of Highways England “The savings are easily calculated as the installation was priced by a pilling contractor at £41,975 and the installation cost of EcoCrib was £24,177 delivering a saving of £17,798 (£395.51/m). Total savings for the M6 project is 270m ( gantry bases) plus 390m ERA’s @ a total of 590m x £395.51p = £233,350 saving. However, other savings and benefits included: Installation time is 30% of alternative products i.e. 2 days against 7 days. Eliminates the need for lifting equipment, allows working in limited spacing, is environmentally friendly, improves aesthetics, and has a product life of 120 years. “ Developed from timber crib technology, the 50mm x 125mm Ecocrib profiles are considerably more durable than treated timber but possess many of the environmental benefits. Ecocrib profiles are manufactured entirely from recycled UK plastic waste with any wastage or surplus material re-processed to form new Ecocrib profiles. Ecocrib can be recycled when it reaches the end of its useful life. 1478 SQM of EcoCrib was used in the scheme equivalent to 17 million plastic bottle tops or 86 tonnes of plastic waste diverted from landfill. Highways England is now looking at the possibility of using EcoCrib for step installations and retaining wall heights higher than 1.5m.