Working in joint venture, HOCHTIEF built a new road between Minster Roundabout and the Lord of the Manor Junction on the A299. We delivered 8km of dual carriageway, new roundabouts and junction improvements, as well as two rail crossings: Cliffsend Underpass and Cottington Bridge.
- 8km dual carriageway
- Cottington Bridge: 115m two-span bridge over rail
- Cliffsend Underpass: 126m jacked box underpass below rail
- £5m utilities diversions
- 20km Drainage, pumping station
- Footways, cycleways
- Large embankments, landscaping
- Detailed environmental and archaeological investigations
- Wetland creation
Cliffsend Underpass – the world’s longest jacked structure – sits six metres directly beneath a major high-speed rail line. As protecting the railway during construction was imperative, we developed an alternative underpass design that involved boring two tunnels through the embankment, lining them with reinforced concrete mini piles to support the walls and roof then pushing the roof slabs into place using large hydraulic jacks and an innovative anti-drag system. We also employed real-time monitoring of the track above throughout construction. Our design and methodology minimised ground movement, allowing us to build the underpass without disturbing railway operations.
We also value engineered an alternative design for Cottington Bridge, reducing it from three spans to a two-span, integral structure made from reinforced concrete and weathering steel, saving money on materials as well as long-term maintenance. We installed the bridge deck’s permanent formwork on the beams at ground level, then lifted the completed beams into position over a night shift, reducing working at height to ensure operative safety.
We delivered the scheme five months early, saved £2.5m and contributed to East Kent Access winning the ICEEngineering Excellence Award 2013 for Innovation.