The East Kent Access Phase Two project was a £87m joint-venture between VolkerFitzpatrick and Hochtief. Brett Concrete was awarded the order to supply the joint venture from March 2010 with volumes in excess of 25,000m3. This contained a requirement to complete six 1,000m3 of concrete for the newly designed Cliffsend underpass, large structural pours ranging up to 350m3 at Cottington Road together with supplies to road and drainage sections of the contract.
Technical Challenge – The Longest Jacked Structure in The World
The Cliffsend Underpass is the major and unique design and build element of the East Kent Access Phase 2 contract. The structure provides a route for the new dual carriageway, which sits in a 15m deep cutting either side of the railway. The proximity of local properties on both sides of the railway meant that an over-bridge solution was not viable.
Box Jacking is a well tested technique for building tunnels and underpasses with minimal disruption to existing road and rail infrastructure. The one at Cliffsend is believed to be the most impressive example of jacking within the last ten years, and the longest jacked structure in the world.
As well as the size of the structure the whole operation took place without a single disruption to trains running in excess of 60mph! The Network Rail infrastructure and especially the railway lines together with the supporting ground had to be constantly monitored. Any change in the railway track alignment even by a few millimetres vertically or horizontally has an impact. If track movement approached the determined thresholds then realignment took place at night during no-train hours.
Brett Concrete worked closely with the main contractors at every stage to ensure that timescales were met, mixes correct and good communication established.
Brett Concrete was awarded the BRMCA's (British Ready-Mixed Concrete Association) award for excellence in customer service and were nominated by the joint venture company VolkerFitzpatrick and Hochtief. Click here to read the full story.