Work is scheduled to begin on site in May for completion in February 2015.
Tony Gee & Partners has produced the designs for the new rail and road bridges and causeway approaches. The new viaduct, located in a Site of Special Scientific Interest and a Special Area of Conservation, will comprise seven 20m integral spans, formed from prestressed beams supported on concrete crossheads and large-diameter concrete piles installed into the estuarine sands and gravels.
Funding from a combination of sources including Network Rail is allowing for a full replacement of the existing structure rather than continuing to make ongoing repairs. The project is being managed by Gwynedd Council.
The current 22-span structure carries the single track Cambrian Coast railway from Dovey Junction to Pwllheli and a single track toll road across the Afon Dwyryd for cars. Heavier and larger vehicles, such as lorries and buses, are unable to use the existing bridge and face an extra 13km journey.
The new structure will continue to carry the single track railway but also provide a two-lane public highway and cycle route and the current toll fees will be removed when the project is complete.
The new bridge will be 18m wide compared to the existing 8.5m-wide structure. It will be built in phases so that train services will not be unnecessarily disrupted. A temporary bridge will also be provided for vehicle crossings.
