Project Description

FP McCann precast concrete Box Culverts provide watercourse channel solution on The Wixams in Bedfordshire

Status: Completed

Location: Bedfordshire

Division: Box Culverts

Main Contractor: ECL Civil Engineering

Market Sector: Housing, Residential, Water


The Wixams in Bedfordshire is one of the UK’s latest and largest new towns sited on 750 acres of brownfield land formerly known as the Elstow Storage Depot a former WWII munitions site. Once complete some 4,500 new homes together with schools, commercial and retail properties will form the heart of the huge development.

L&Q (formerly Gallagher Estates) based in Warwickshire is the mainland developer. The site has been split into four separate schemes, Villages 1 to 4.

Currently under construction is the £11 million infrastructure programme on Village 3 which includes major civil engineering work to parcel the land for 2,000 homes. Some 16.5km of foul and storm drainage is required, 40,000m² of adoptable carriageway and 5 precast concrete culvert runs totalling 152 linear metres. Due to the existing network of brooks and waterways running throughout the site, Bedford based groundworks specialist ECL Civil Engineering has had to construct a number of load-bearing crossings to carry water beneath the planned road network with minimal disruption to the natural flows.

With significant vehicle loadings on the site roads during construction, precast concrete culvert box sections were the clear choice to channel the watercourses beneath. Following discussion with FP McCann’s box culvert design team based at Weston Underwood in Derbyshire, ECL’s project engineers in conjunction with civil engineering consultant Hydrock adopted two box culvert section sizes; 63 units measuring 1800mm wide x 1500mm high and 13 larger sections measuring 4800mm wide x 2400mm high. With each of the 13 large units weighing in excess of 23 tonnes, single section loads were delivered to site and installed by a specialist crane to form a 26-metre culvert beneath the main access road to the site. Each unit has been bitumen paint coated externally for added waterproofing. The smaller precast box culvert sections have been used to form four other watercourse culverts on the development.

Commenting on the installation, Robert Wharton senior project manager for ECL Civil Engineering says, “The box culvert team at FP McCann has successfully helped to design an offsite precast concrete solution to successfully manage the natural watercourse channels on this development whilst providing load-bearing vehicle crossings. The units were quickly and simply installed and it demonstrates the flexibility that concrete box culvert sections can offer.”