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Prototype AVA adaptable modular footbridge completed for Network Rail

Construction of the prototype fully accessible AVA modular footbridge, which has the potential to disrupt the way rail footbridges are designed and delivered, has completed.

The AVA Footbridge and Lift system was designed by the AVA Consortium, which features Expedition Engineering, Hawkins\Brown, Walker Construction, Network Rail, McNealy Brown and ARX.

It was designed with the intention of revolutionising the way that footbridges on the rail network are constructed, providing a cheaper, more efficient and more sustainable design that is fully adaptable and accessible. This was the challenge laid down by Network Rail, which was looking to reduce its capital expenditure, carbon footprint and installation times of footbridges while completing its Access For All programme.

The consortium describes the bridge as a “high-quality architectural piece suitable for any station environment”. It features an integrated lighting system, glazed screens and an exposed bead-blasted stainless steel finish and cladding that gives it a 120 year design life.

Most importantly, its modular design means it can be reconfigured for any arrangement to match the site’s needs. The bridge span, for example, is made of 1.2m long segments that can be bolted together to the required length up to 20m. The finer details of the length can be adjusted on the end modules. Spans longer than 20m can be formed with a bespoke arrangement.

ava-footbridge-modules-steps.pngava-footbridge-modules.pngThe staircases can also be adjusted with the addition of more steps if a greater height is needed to clear overhead line equipment.

Additionally, the lifts can be placed where required to suit the platform arrangements. The lifts are fully assembled and tested before being transported to site for installation and commissioning with minimum disruption to the station.

The modular construction also enables the bridge to be de-constructed and re-constructed elsewhere, or for parts to be re-used.

ava-footbridge-configurations.pngAVA Consortium says that the total site time needed to full construct the bridge and bring it into service is 15 weeks, subject to site access, which is less than half the time of industry standard for new footbridges. This is aided by the lift pits being shallow and the components being “plug and play”.

The actual installation time is 36 hours, with a target of reducing this to 27 hours. This is enabled by the components arriving on site already fully commissioned and the connections between modules being made by bolts rather than welding. Bolting also reduces the need for specialised workers.

ava-footbridge-installation.pngAVA Consortium says that the time from contract award to handover is 20 months – a 58% reduction on a typical four-year procurement programme. This is enabled by reduced approvals time, reduced design period, reduced certifying time and reduced site time.

As well as having a 120 year design life, the AVA modular footbridge requires much less maintenance. Thanks to the corrosion free stainless steel, toughened laminated glass and aluminium walking surfaces, it is said to only need minor maintenance once every 25 years. This is because it will never need to be re-painted or re-coated, which also means no possessions are necessary and major disruption to the station is eliminated.

The AVA Footbridge has been featured in the latest version of the Network Rail Footbridges & Subway Design Manual. An independent assessment of the bridge commissioned by Network Rail awarded it maximum points for sustainability, passenger experience, safety, maintenance and costs compared to other footbridges.

Going forward, the AVA Consortium believes that there will be incremental improvements to the design. This will build on real world testing and analysis of the data gathered, along with focus on scalable production and reducing costs.

The current capital cost of the AVA Footbridge is around £2.5M to £3M, dependent on configuration. This can be reduced if Network Rail starts batch procuring its footbridges, allowing economies of scale to be realised through modern methods of manufacturing when production ramps up.

 

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Asymmetric bridge showing two configuration options to test maximum adaptability (Copyright AVA Consortium)

Expedition Engineering and Useful Simple Trust director Eva MacNamara said that the AVA Footbridge and Lifts System “demonstrates a transformation in productivity, performance and quality, essential for revolutionising the industry’s approach to modernising the provision of UK infrastructure”.

She continued: “Following substantial industry interest in both the innovation process we have been through, and the AVA ‘adaptable product’ outcomes, we are proud to unveil the AVA Footbridge and Lifts demonstrator—a direct response to Network Rail’s challenge statement for ‘Access for All’ Schemes.

“Moving forward, we anticipate a robust demand pipeline that leverages AVA’s design and construction principles, capitalising on manufacturing efficiencies through batch procurement, economies of scale, and incremental enhancements. Our commitment remains unwavering: to deliver cutting-edge value in the transformation of UK infrastructure.”

The first official order of the AVA Footbridge is from Greater Anglia, which will have one installed at Stowmarket station to replace the ageing concrete footbridge.

Revisit our 2021 feature about the development and benefits of the Ava footbridge.

 

AVA-Night01_copyright-the-AVA-Consortium.jpg

Asymmetric bridge showing two configuration options to test maximum adaptability (Copyright AVA Consortium)

Thanks to New Civil Engineer