One of the largest civil infrastructure projects in the UK for many years, the Mersey Gateway Bridge uses a triple-pylon cable-stayed concrete structure with integral multiple-span approach viaducts to provide a much-needed north-south link between the boroughs of Halton and the central Liverpool City Region.
The bridge represents the ‘next step’ development of established technologies but is also uniquely innovative in its own right in several ways.
The judges were impressed by the use of the modified self-launching moving scaffold systems, each weighing around 1,350 tonnes, which allowed the progressive casting of the 70m approach viaduct spans, thus delivering substantial cost and programme savings.
Impressive too was the use of travelling ‘C’-shaped formwork, which allowed access to the upper surface of the deck modules, as these were progressively cast above the Mersey in a balanced sequence to either side of the central stay pylons.
Advanced material technology, coupled with complex thermal and creep analysis allowed the approach viaducts and main river crossing spans to be cast in one uninterrupted length of 2.25km without intermediate movement joints.
Exemplary collaborative integration between the client, design and construction team members, using a unique PPP procurement strategy, delivered sufficient cost savings to enable the crossing to be toll-free for borough residents.