The Dutton Viaduct was built by Joseph Locke from designs by George Stephenson, to carry the Grand Union Railway over the valley of the River Weaver in Cheshire, and was completed on the 9th December 1836. Kaymac Marine and Civil Engineering Ltd were commissioned by Birse Rail to carry out scour protection works to the two spans of the viaduct which now carry the railway over the Weaver Navigation. Previous inspections had revealed river bed scour, undercutting of a pier base and widespread open jointing both above and below the waterline.
Access to the project was of a major concern, with the nearest available point for transporting materials and plant being 4.5 miles West of the structure at Frodsham.
Pontoons were used to provide working platforms for a diving station and a small excavator, with a hopper barge used to transport stone to the work site from the loading area in Frodsham. A NATO type tug ensured the safe transport of plant, materials and personnel to and from the worksite. Our own dive teams were used to fit temporary formwork to enable the placing of 6m³ of underwater concrete as underpinning beneath the undercut pier base. The divers then cleaned and repointed the open joints in the masonry below water using specialist products. The excavator, working from a pontoon stabilised with hydraulically operated spudlegs, placed 60t of stone in two areas of river bed scour, the formation and finish levels kept under close tolerance by the divers and engineer. Finally, the structural elements adjacent to the water course was cleared of vegetation and repointed using a mortar injection system.
The works were carried out within the programmed period, and within the project budget. The client, Birse Rail, were so satisfied with the professional approach of Kaymac to the project and the quality of the finished works, that a five star report was submitted by Birse to Network Rail, the ultimate client and owner of the Dutton Viaduct.