ABG Deckdrain A14 Structural Drainage

Status Completed

Location Cambridge to Huntingdon

Start date 01/11/2016
Completion 06/02/2020

Project requirement The A14 is a strategic trunk road which runs between the M1 Catthorpe Interchange and Felixstowe. The A14 is dual carriageway for most of its route and carries up to 85,000 vehicles per day, of which many are HGVs heading to the Port of Felixstowe. Volumes of traffic are now much greater than were anticipated by the original design. The stretch between Cambridge and Huntingdon is one especially prone to peak time delays and has a poor safety history. Highways England, along with their delivery partner A14 Integrated Delivery Team, are upgrading the carriageway to improve safety, improve air quality and unlock development potential in the area. The project involved the construction of a number of structures which were on the key timeline of the project. Many of these structures were of a considerable size and required structural drainage that could be rapidly and safely installed. Traditional methods such as porous blocks were deemed to be slow to construct, and posed a high risk of damaging the waterproofing when being manoeuvred into place. Manual handling equipment is required to install traditional systems and construction output is typically low. Furthermore, due to their size and weight, moving materials around on site posed significant logistical problems. Other options considered, such as no-fines concrete, required formwork and were expensive to place. Often additional earthworks operations are required further slowing scheme progression.

Services supplied The Contractor recognised the successful use of ABG Deckdrain drainage geocomposite on previous schemes and proposed its use to the consultant and Highways England. On this project the high strength 7,000m2 of Deckdrain 750S/NW8 and Deckdrain 1250S/NW8 were chosen to withstand anticipated passive earth pressure movement. Deckdrain allowed for safer installation compared to porous blocks as there is no need for heavy machinery due to it’s lightweight and easy to handle nature. This in turn reduced installation time, labour costs and vehicle movement on site. ABG provided technical support to aid product selection and gain approval from Highways England. ABG and the A14 Integrated Delivery Team entered the Deckdrain concept and were shortlisted for the Sustainability Category for the 2019 Construction News Awards .

Costs- £100,000

Outcomes • Reduced labour & plant costs • Reduced pollution resulting from site plant and delivery vehicles • Rapid installation • High flow capacity • Protection to waterproofing

The embodied carbon (C02e) realised through installing Deckdrain amounted to 4.17T which compares to 49.7T if hollow block had been used and 119.8T if no fines concrete had been used.