Composites
Is Futura the perfect solution for the next generation of footbridges? Network Rail Principal Engineer Ian Grimes speaks about the future of footbridge design
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n our rush to get to the right platform or make our way out of the station as quickly as possible, the majority of us do not give much thought to railway footbridges. We might admire the staying power of Victorian engineering and architecture, or the functionality of a footbridge constructed in more recent times, but, more often than not, as we move swiftly across them, we barely consider how inaccessible some of these structures are. As Network Rail contemplates the design and engineering of its estate in order to replace footbridges no longer fit for purpose and to construct new footbridges, it does so against the backdrop of Construction 2025, the joint strategy from government and industry for the future of UK construction, which focuses on the use of smart technologies, green construction and overseas trade. Construction 2025 targets More specifically related to railway footbridges, Construction 2025 targets aim to bring about 50 per cent faster delivery, a 33 per cent cost reduction, 50 per cent lower carbon emissions and a 50 per cent reduction in the import/export trade gap. All of this is being pondered by Ian Grimes, Principal Engineer in Network Rail’s Technical Authority for Buildings and Architecture, as Network Rail look to prototype Futura, the concept footbridge designed by Marks Barfield Architects and COWI. The Futura footbridge will demonstrate the benefits that can be gained from using composites in railway station environments for both new build and replacement structures. Ian said: “We’ve been doing a lot of work around updating the designs of our standard footbridges. In recent years there’s definitely been more of an architectural focus and an interest in creating bridges that are more aesthetically pleasing. While this has included steel bridges, we’ve looked at reducing carbon and our reliance on steel. “With net-zero targets we’re exploring different materials, and composites lend themselves to a more modular approach. A modular approach to construction reduces 22 | December 2020
time on site and we’re not just looking at virgin materials, such as carbon fibre and glass, but want to explore a circular economy where, for instance, we can strip down end-of-life wind turbines and reissue and recycle those parts into a footbridge component. It’s an approach that reduces the environmental impact of construction.” Network Rail has partnered with the National Composites Centre (NCC) to develop factorymoulded fibre reinforced polymer (FRP) bridges, a sustainable solution that will contribute to net-zero targets right across the industry.
There’s a lot of pride in the rail network and we want to build on that and enhance the heritage Network Rail became the first public sector Tier 1 member of the NCC, and both organisations are aligned in their desire to increase the use and adoption of composites in construction. Ian said: “Composites are misunderstood and we certainly want to address that. Around four years ago there was a move by Network Rail to explore the benefits of using composite materials, which had been relatively untried in construction and there was a reluctance
to take them up. We used composites across some isolated schemes and projects but we ran into some issues; they were actually taking longer than traditional methods, needed more technical assurance and, because they were novel, costs were actually higher and we didn’t fully understand their environmental impact. “So we had to come up with ways of managing that, which led to us approaching the NCC. We wanted to be at the forefront of the challenge and also make sure that regulation and traceability was in place. Along with the NCC we’re looking at putting together guidance regarding where composites can be used, and where they won’t provide the best solution, as well as carrying out life-cycle analysis and really understanding what the environmental impact of using composites is.” Access for All Ian added that, in Ian Crockford at Marks Barfield, responsible for the London Eye, and COWI’s Ian Firth, the former president of the Institution for Structural Engineers, the development of the prototype bridge “is in good hands”. Together, the team are also addressing the very important issue of accessibility, in line with the Department for Transport’s ‘Access for All’ programme, and all of these bridges will have lifts. Ian continued: “There are still a lot of Victorian-era bridges in place but we’re now at the stage where they no longer owe anyone railbusinessdaily.com
