Project Activity:
Drainage Surveys and non-intrusive repairs.

Summary of Works:
The 2-year scheme comprised of non-intrusive drainage repairs to the surface water drainage system on the M11. Works were undertaken along large sections of both the northbound and southbound carriageways, central reserve and verges between J7 and J8.

Previous surveys had identified a significant quantity of defects with the proposed method of remediation being ‘dig out and replace’. As part of the ECI process Crown Plus reviewed the surveys and provided new working methodology to the client, Eurovia, as an alternative to the intrusive repair’s methods proposed.

Defects included pipe displacements, presence of settled deposits and other obstructions causing up to 90% cross sectional area loss, broken pipes, fractures, cracks, and open joints, with rehabilitation of the pipelines essential for the drainage network to restore the free flow of surface water within the system and to ensure that surface and sub-surface water is routed away from the road construction.

The new methodology, utilising cured-in-place-pipe (CIPP) and UV lining techniques as opposed to traditional dig-down methods, reduced the original construction programme by 144 shifts. The scheme had previously required permanent lane closures with the installation of VarioGuard, however the methodology meant the following was minimised, producing millions of pounds in financial savings to the client: 

• Impact on road users
• Cost reduction in labour and plant
• Reduction of CO₂ emissions
• Reduced operational hours
• Reduced risk for operatives working on the roads
• Removed the need to import new aggregate and concrete.

Gary Price, Operations Director at Crown Plus said “We are especially proud of our involvement in the M11 project as we were able to fully demonstrate the benefit of our ‘smarter working solutions’. When reviewing the existing scheme information during the ECI stage of the project. Our approach provided our client with approximately £3 million pounds worth of savings across the scheme as a whole. This coupled with the major environmental benefits we enabled certainly makes it a scheme to be proud of”.