The replacement of Loughor viaduct represents a major investment for Network Rail and is required to enable the Gowerton redoubling scheme in South Wales. The existing viaduct, a Grade II listed structure with main plate girders, a timber deck and timber trestle foundations, was assessed and found to be incapable of carrying the scheme’s new twin track arrangement.
Tony Gee was appointed to undertake the permanent and temporary works design of the replacement structure; a scheme that involved an innovative approach to articulation and track structure interaction. The new bridge is a through girder construction with a concrete/steel composite deck supported on reinforced concrete cross heads and piles. One of the most challenging aspects was to produce a design and sequence that could be built in advance of the main rail blockade. The new bridge was built alongside the existing structure and launched in stages across the estuary.
Once completed the structure was slid laterally approximately 15m into its final position. The existing natural stone abutments and some of the listed trestles have been retained and a small section of the old Loughor viaduct erected on the West shore.