Refurbishment design and specification, including the remediation of defective structural members, for this historic lattice girder passenger footbridge.
Llanfairpwll Station is a popular tourist attraction due to its full name, which translates to “St Mary’s Church in the hollow of white hazel near a rapid whirlpool and the Church of St. Tysilio near the red cave”.
The station footbridge was constructed over 100 years ago with cast and wrought iron members. A temporary footbridge was installed and the existing footbridge was removed using a crane and slings and transported to the contractor’s workshop for refurbishment.
Part of the client’s brief was to explore the possibility of replacing the severely corroded steel treads and deck with a GRP alternative satisfying a live load of 5kN/m². We worked to develop a cost-effective GRP solution for the deck and treads to extend the service life to at least 25 years with minimal maintenance costs. This solution utilised a foam core box beam made from glass polymers surrounded in GRP/FRP (glass/fibre reinforced plastics) forming the structural beams. A prototype was manufactured with a 1.8m span and it was sent for independent load testing which showed it satisfied the loading requirements and network Rail.
The product was advertised in IStructE’s January 2017 publication of ‘The Structural Engineer’ and the August 2017 publication of ‘Rail Engineer’ magazine, alongside a case study written by Network Rail’s Route Asset Engineer. The case study can be found via: https://www.railengineer.uk/2017/08/18/the-worlds-longest-footbridge/.
Project Value: £0.5m
Client: Network Rail
- Footbridge inspection.
- Development and approval of innovative GRP/FRP solution for deck and treads.
- Non-complex design submission:
- remedial design to extend the life of the footbridge and repairs to defective members.
- Inspection and attendance at workshop to agree replacement members and refine design proposals.