Arlesey Footbridge
Bedfordshire, UK
Project synopsis
The Arlesey Relief Road scheme for Central Bedfordshire Council (CBC) including a pedestrian, cycle and equestrian access route in an area comprising of a new footbridge across the A507 on the eastern edge of Arlesey Cross.
Contractor
John Sisk & Sons
End client
Central Bedfordshire Council
The Arlesey Relief Road scheme for Central Bedfordshire Council (CBC) was to provide new infrastructure in support of a new development zone which comprises an allocation for 1,000 new homes and 10 hectares of commercial activity.
John Sisk and Sons Ltd (Sisk) were appointed to take the footbridge forwards through to construction as a design and build contract with Tony Gee appointed as their designer.
The 57.5m superstructure has a clear width of 3.5m between parapets and main arch span of 34m, consisting of a steel thrust arch with stiffened steel deck and approach spans at either end which connect to new embankments formed from site won material. The steel arches are fabricated from steel 457mm diameter hollow sections and the deck is formed from steel plate on transverse crossbeams, supported on hangars over the arch span, with the back spans supported by steel columns between the arch and end support.
Whilst the contract did not have specific BIM requirements we took a decision to utilise Revit for all of the structural design utilising existing knowledge gained on other projects combined with existing 3D topographic information and highways Civil 3D models to coordinate the design from the outset. This early investment paid off later when we were able to utilise the models to support Sisk with further construction sequencing and
coordination using Navisworks for CBC.
The preliminary design of the scheme and planning stages were completed by Jacobs on behalf of CBC. The design has been a joint effort delivered with Esher highways, geotech and the structures out of the Ashford office.
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