The Mersey Gateway road bridge across the River Mersey in North West England will provide a new link between the towns of Runcorn and Widnes and speed journey times for those travelling further into Liverpool and Merseyside.
Due to be opened to traffic in Autumn 2017,
Work has started on the approach viaduct decks with the first continuous 34 hour pour of 1,148m³ concrete having just taken place. An innovative moveable scaffold system (MSS) has been used by Merseylink to build the concrete approach viaduct decks and the Cemex team in partnership with the contractors, is providing the technically demanding concrete and supply expertise.
The MSS is 157m long, 22m wide, weighs 1,700tonnes and is a giant section of formwork, enabling the project team to cast deck spans of up to 70m at every location. Once poured the MSS jacks itself forward to the next span.
Each deck span requires more than 1000m³ of concrete and has a complicated cross-section. Therefore, every pour requires a similarly exacting placement pattern to ensure the C50/60 concrete hardens homogeneously across the deck. Using CEMI and a bespoke admixture combination will ensure, consistence retention, where required and high early age compressive strength.
“Mersey Gateway is a highly complex engineering project and one of the biggest in Europe, for which we, in partnership with Merseylink, have developed a suite of concrete mixes that will meet the performance criteria for this amazing infrastructure.
“The approach deck span requires a consistent C50/60 concrete with two hour consistence retention and 32 MPa at 36 hours to enable post-tension stressing” comments Richard Kershaw, Cemex national technical manager.
The continuous pour of 1148 cu metres was fed by two mobile batching plants set up by the Cemex engineers close to the construction sites. These have been established one on each side of the river, to accommodate work on the scheme. This first MSS pour was on the North Approach Viaduct using the North Batching Plant on the Widnes side of the crossing.
The first pour has now been completed but with the MSS already being readied for the next there’s plenty more concrete to be batched.
