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SSDA 2016

NATIONAL FINALIST Strabane Pedestrian and Cycle Bridge, Co Tyrone Architect: WYG/Doran Consulting Structural Engineer: AECOM Steelwork Contractor: S H Structures Ltd Main Contractor: Fox Contracts Client: Derry City and Strabane District Council This bridge provides a key link between the town centre and the residential and sports areas to the south. The cable-stayed bridge cleverly cantilevers from the south side, minimising the impact of foundations on the north end with its busy roads and critical infrastructure services. A striking steelwork project. PROJECT TEAM Architect: Universal Design Studio Structural Engineer: Heyne Tillett Steel Steelwork Contractor: Ermine Engineering Main Contractor: Parkeray Client: The Science Museum This imaginative design which achieves its supports from existing columns has been carefully detailed, assembled and installed into a highly constrained existing gallery space. The merits of steelwork and the close collaboration between the designers, contractors and an informed client have all contributed to success. PROJECT TEAM The key structural element in the new Information Age Gallery is a raised elliptical walkway which runs throughout the gallery and bridges the spaces in between six interactive ‘story boxed’ zones. Primary support is provided via these steelframed ‘story boxes’ and additional intermediate supports off existing columns, with seemingly invisible connections giving the illusion of the walkway piercing uninterruptedly through the pods. The deck comprises a simple curved box ‘spine beam’ with regularly spaced cantilevering ‘ribs’ at either side, which was well equipped to handle torsion generated by the plan curves and eccentric column supports. The walkway was delivered as a series of 6.2m long cassettes with the cantilevering ‘arms and glass balustrade supporting edge members prewelded to the ‘spine’ offsite. These were lifted into position using spider cranes and connected via full strength butt welds. This landmark cable-stayed bridge crossing the River Mourne provides a crucial missing link for pedestrians and cyclists between the residential areas and schools south of the river and Strabane centre to the north. A key feature of the inclined and curved main pylon is a wishbone-shaped pair of Vierendeel trusses that stiffen the top of the arch in this zone of highly focussed loading. The designed profile of the pylon legs was parabolic. This shape was approximated during fabrication by three constant radii, with a discrepancy in geometry of less than 10mm, making fabrication of the pylon more efficient and cost-effective. Offsite fabrication produced a polished, precision-fabricated structure with the desired aesthetic qualities, as well as minimising site activities. The installation of the mast required two large mobile cranes to safely carry out a critical and complex tandem lift. © Peter French NATIONAL FINALIST Information Age Gallery, The Science Museum, London JUDGES’ COMMENT JUDGES’ COMMENT


SSDA 2016
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