The project involved the construction of a 63m single-span bowstring truss footbridge over the Pennyburn Inlet and the development of a 660m greenway link connecting Derry City to Muff, County Donegal. This project is a key segment of the 46km Northwest Cross-Border Greenway, funded by the Special EU Programmes Body (SEUPB), and was led by Derry City and Strabane District Council.
The £2 million structure enhances connectivity between the River Foyle walkway and Bay Road Park, supporting both pedestrians and cyclists while integrating with future development at the former Fort George British Army Barracks.
Key Aspects of the Project
• Footbridge Design and Structural Considerations: Design ID served as Principal Designer and Lead Footbridge Designer, delivering a 63m bowstring truss footbridge for pedestrians and cyclists. A comprehensive dynamic analysis ensured that the bridge caters for large events like the Derry City Half Marathon. Design ID in collaboration with the Steel Fabricator's Designer, took a pragmatic approach to specification of the bridge geometry to achieve this, whilst also allowing for future installation of a Tuned Mass Damper. This helped to optimise weight and structural efficiency in the first instance, whilst offering a mitigation strategy should more extreme footfall events be experienced over the design life of the structure. Wind action and aerodynamic effects were also assessed, confirming no requirement for wind tunnel testing or the associated bridge excitation.
• Greenway and Civil Infrastructure: The project included 650m of new pedestrian and cycle paths, integrating with existing networks in Bay Road Park. Work covered drainage systems, scour protection, embankment stability, road markings, and signage, overcoming challenges posed by the brownfield industrial site and historic infrastructure.
• Technical Approvals and Compliance: Design ID secured key statutory approvals, including Approval in Principle (AiP) for the footbridge and drainage approvals with DfI Rivers and Loughs Agency. Environmental risks were assessed and mitigated through sustainable design strategies.
• Construction Logistics: Temporary works design included the design of working platform, placed on top of an existing revetment structure to facilitate erection of the bridge structure. This platform was designed in support of an impressive, 800T Liebherr LTM1800D Mobile Telescopic Crane, which was transported from mainland Europe and built at the project site. A whopping 160T of crane counterweight was required to erect the structure at its lifting radius.
Client: FP McCann
Structural Detailer: Stuctural Design & Detailing
