Network Rail (NR) sought new ideas for the design and installation of fully accessible pedestrian footbridges across the UK rail network. The aspiration was to generate a catalogue of appropriate footbridge designs affording greater flexibility for sites across the country. NR owns about 2,400 footbridges providing access across the railway for both passengers at stations and people using rights of way.
Most of these footbridges are single-span structures, with the majority having a main span of 16m or less. With the electrification of the network has come taller footbridge structures which take longer to cross and have a greater visual impact. While not primarily intended for use in conservation areas or listed building settings, the design aesthetic needed to be suitable for all situations.
The railway environment creates unique challenges for designers, including a constrained construction site with many considerations to ensure passenger safety and comfort. Disruption to station infrastructure and activities needs to be minimised and long-life and low maintenance are priorities.
Our design uses fibre-reinforced plastic (FRP), which is an ideal material; affordable and with a high strength-to-weight ratio, which reduces the amount of raw material required. This ensures a lightweight structure, which is easier to transport and install. It is non-conductive and therefore safe in electrified areas. It also requires minimal maintenance and is resistant to corrosion, fire and discolouration. FRP is most efficient when formed as a tubular structure.
Our proposal is based on this principle, using filament winding to form FRP around a cylindrical mould. The distinctive character is a result of this process. Forces are legible, with structure provided only where necessary, maximising perforations to light, air and views. The process is suitable for one-off and high volume, with the length adjustable for various scenarios. All additional elements and services are carefully integrated within, creating a clean and crisp aesthetic. A transparent panel is used to provide safe edge protection along the length of the bridge.
The same approach is applied to the stair and lift. These are economical to fabricate from pultruded and moulded section of FRP. Modules are scaled for transportation on a flat-bed lorry, with pre-fabrication reducing the time on site.
The structure of the lift core bears the load of the bridge, enabling it to be quickly craned into place and minimising disruption to both operations and existing infrastructure. The strategy creates a catalogue of flexible components that can be combined in site-specific combinations. The pattern can be varied and the colour specified, allowing for either a passive structure or a prominent landmark.