Major Step For The Mersey Gateway Project - continued
Construction of the foundations involved making a concrete base layer – or floor – inside the cofferdams. Following this, a cage made of steel reinforcing bars was assembled and encased in steel matting. A work platform was also installed to provide access for site workers.
Upright steel reinforcement bars were then fixed into the centre of the cage to form the beginnings of the pylon shaft that will rise out of the riverbed to support the bridge deck. Once the assembly work was finished the concrete pour took place.
Merseylink's site agent, George Houston, said:
This was one of the biggest concrete pours that I've ever been involved with. We used a massive amount of concrete – over 600 truckloads just for the three pylon foundations. It was an extremely technical part of the project and our teams worked round the clock to get the job done.
In total, approximately 127,000 cubic metres of concrete will be used across the project. That's the equivalent of around 20,000 truck mixer loads of concrete.
Every single batch of concrete was rigorously tested at the project's UKAS accredited site laboratory to ensure that the mixture is the right strength and composition.
Once set, the next stage can commence. The formwork will be lifted into place by a crane and attached to the pylon foundation ready for the concrete to be poured into.
The formwork will move up the pylon shaft with each section of the shaft taking around five days to build.