20 December 2013
20 December 2013
The Institute of Civil Engineer’s South West Minor Project of the Year Award 2013 has commended the use of fibre-reinforced-polymer composite (FRP) in the footbridge structure, which was originally designed by Isambard Kingdom Brunel in 1830 and is grade II listed.
Unfortunately, the station’s steel footbridge, reconstructed in 1937, had deteriorated beyond economic repair and any replacement would need to be able to withstand the harsh elements of this exposed stretch of the Devon coastline.
The team challenged with delivering a solution was principal contractor BAM Nuttall, main designer Tony Gee and Partners with sub consultant Optima Projects, and bridge fabricators Pipex px, working in partnership with Network Rail.
According to Tony Gee and Partners, a new steel footbridge had been considered, but while this could be detailed to reduce the susceptibility to corrosion, the location was such that it could only restart the continued (and probably unwinnable) battle. Instead, a wholly FRP structure was proposed. This would both simplify installation (at only five tonnes, the new bridge weighs a third of the original) and, more critically, the extreme durability and corrosion resistant properties would significantly reduce whole life maintenance costs.
Two overnight possessions were planned; firstly for the removal of the existing steel footbridge and a week later for the new bridge to be installed. Both ran ahead of schedule with the line available to hand back to Network Rail several hours earlier than planned.
The designers explain that the scheme has provided the local community with a safe, attractive and sustainable new footbridge, expected to result in considerable through-life cost savings due to reduced maintenance expenditure. Aesthetically replicating the character of its predecessor, it is the first FRP composite bridge to be installed at a mainline station in the UK and notably the first grade II listed FRP bridge. The benefits realised in using modern advanced materials technology have triggered Network Rail to consider FRP solutions for two further footbridge replacement schemes in similarly exposed coastal locations.
Photo courtesy of Tony Gee and Partners