Parkway/M602 link : lift bridge over the Manchester Ship Canal. Paper 2. Design and construction

This paper explains the design and construction phases of the proposals accepted by the Client under the design: construct form of contract. The Engineer's brief had stated a preference for a horizontal swing bridge, but that with specific pre-tender submission an alternative form would be acceptable. Accordingly, swing bridges and other forms of moving structure were examined carefully to determine the most appropriate and economic solution in consideration of the constructional, aesthetic and maintenance viewpoints. A single (44 m) span vertical lift bridge was concluded by the Contractor to be the most desirable and economic solution, in spite of the fact that only one other reasonably modern example of its type exists in the UK. A perceived advantage of a vertical lift bridge was that all the mechanical equipment could be fully sheltered from the elements. The deck of the bridge is of all steel construction, designed for speedy erection over the canal during a possession period and balanced by counterweights housed within hollow reinforced concrete towers at each corner. Lifting is activated by synchronized winches through a rope drive connected to each counterweight and concealed within the abutments supporting the towers. Foundations comprise large diameter concrete piles taken into bedrock. New river walls are formed using tied sheet pile walls, and wingwall approaches are of reinforced earth construction.