A 220m long steel and concrete deck has been installed to complete the Lower Thorpe HS2 viaduct. The 1,300 deck was placed using structure sliding techniques.
A 220m long steel and concrete deck has been installed to form the Lower Thorpe viaduct, which is part of the HS2 project near the Northamptonshire village of Thorpe Mandeville. The 1,300 deck was placed using structure sliding techniques. The operation took three days to complete.
The deck was slid sideways with the aid of special pads coated with polytetrafluoroethylene (PTFE), which is similar to the material used to make non-stick frying pans. This reduced friction between the deck and the temporary support structure of steel bearings placed on five concrete pillars.
The next phase of the operation will involve lowering the deck onto the permanent bearings. The installation is the final of five viaducts that have been constructed using the same sliding method. In total, the completed HS2 project will have 15 major new viaducts. The planning and preparation for the Lower Thorpe slide took four years.
HS2 Ltd’s project manager, Sam Arrowsmith, said: “The slide may only have taken three days, but it was the culmination of four years of work – developing the design, completing the groundworks and the piers and assembling the enormous steelwork.”
HS2’s main contractor is EKFB. Technical Director Janice McKenna said: “The strategic design approach applied to these double composite structures has been a game-changer in how we’re building these viaducts.”
“The double composite solution can be applied to multiple structures in different locations, and we have five across EKFB’s 50-mile route that are all well into construction.”
The viaduct will carry high speed trains across Banbury Lane, and is made from russet-coloured weathering steel to help it blend into its surroundings. It will reduce journey times, and also help to manage flood risk by allowing rainwater to run off into existing water courses.