Site: A556 Knutsford - Bowdon, Cheshire
Client: Highways England
Products supplied: Precast concrete drainage and stormwater chamber systems
Work to improve the busy A556 trunk road between Knutsford and Bowdon in Cheshire by creating a new modern dual carriageway by-pass to the existing road has recently been completed. Highways England and their Tier 1 supplier Costain opened the new £192 million dual carriageway in March this year. The 7km road will carry some 51,000 vehicles a day and link the M6 at junction 19 to an improved junction 7 on the M56.
Helping Costain keep on track in delivering the road scheme on time, FP McCann has supplied a full range of precast concrete chamber systems manufactured in quality controlled factories and delivered to site as called off by the contracting team. In total some 750 precast concrete catch pits, Easi-Base units and flow control/penstock chambers have been delivered.
More than 600 DN1200 through to DN1800 diameter catchpits have been installed along the route. The pre-cored catchpit base design allows the contractor to quickly form an integral sealed sump system without the requirement for the delivery of wet trades such as ready mixed concrete and mortars. This means significantly less vehicle/person interface on site and the factory built units are more carbon and environment friendly as fuel and traffic movements are reduced.
Pipework can be quickly connected and the chamber rings placed on top to safely and efficiently complete the build. Using the 130mm wide wall manhole ring in conjunction with both the catchpit bases and Easi-Base units meant that the chambers didn’t have to be surrounded with concrete, increasing productivity on site and helping Costain under COSHH directives to minimise the exposure of operatives to a hazardous substance. As no powered saw cutting is required to form inlet/outlet points the precast chambers eliminate hand-arm vibration syndrome (HAVS) and there is no risk of airborne silica in any dust.
Over 100 Easi-Base units were also installed. Both the polypropylene lined DN1200 and monolithic DN1500 and DN1800 units are pre-benched and channelled again allowing for efficient and safe installation.
Commenting on the FP McCann chamber systems, Sean Ellison senior site agent for Costain said, “These off-site manufactured precast concrete chamber units have helped significantly in us achieving our build programme and on site safety targets. They are simple to install and the integrity of the finished sump and base units together with the benefits of the cast-in pipe openings and seals gives us the confidence that these precast concrete chambers will form part a long life, low maintenance drainage system on the A556 link road”.
Note: FP McCann’s offsite manufactured precast concrete drainage chamber systems have been accepted onto the Highways England project efficiencies register and shared through the HE Knowledge Bank Portal across other major highways infrastructure schemes.