Comprising of 19.6km of dual carriageway, including nine new roundabouts, seven new bridges and an underpass, the Norwich NDR is the largest privatised road project outside of the local authority remit in the UK. The new road will improve traffic flow on the northern section of Norwich’s outer ring road, and the scheme will also provide the required infrastructure to allow the planned growth for new housing and business within the city to begin.
Polypipe CGU worked closely with the main contractor, Balfour Beatty, on behalf of Norwich City Council, to design and manufacture a tailored solution, taking advantage of the high-quality value engineering available within Polypipe CGU’s Ridgistorm-XL and Ridgidrain systems. The final design ensured that surface water from the new road would be captured before it could form a pool and then be carried through a number of drainage runs and into the existing sewer network.
Polypipe CGU’s Ridgidrain system was supplied to manage the surface water gathered on the road, with the product specified in diameters ranging from 225mm to 600mm. Plus, the project benefits from Ridgidrain’s status as the first twinwall surface drainage system in the UK with Highways Authority Product Approval Scheme (HAPAS) status. Over 350 catchpits with 100mm and 150mm inlet/outlets were also installed and then connected to Polypipe’s Linflex Type 8.
Polypipe CGU also supplied 384m of Ridgistorm-XL large diameter plastic pipework in 750mm diameter, which was installed beneath the central reservation on the main carriageway. The pipework was manufactured to the ideal stiffness specification to handle the ground conditions on site and provided considerable installation savings by minimising the volume of imported granular fill needed for other types of pipe. This system will efficiently deal with the conveyance and attenuation of stormwater on the road’s new surface.
The site and surrounding area was functioning as a road to the general public throughout the construction and therefore there was a need for installation to be quick and easy. Due to the light-in-weight nature of plastic and the ability of Polypipe CGU to design and deliver products direct to site at the precise time they were required, the solution ensured efficient installation. Polypipe CGU was able to deliver these benefits thanks to its plastic systems, provided as an alternative to the initially specified concrete.