New bridge road deck takes shape
WORK has started on the outer road deck of the Mersey Gateway’s north approach viaduct as the first of more than 60 concrete pours took place.
A wing traveller machine is being used to build the outer road lanes on either side of the north approach viaduct in Widnes.
It will follow the project’s movable scaffold system (MSS), which is constructing the central part of the carriageway.
The wing traveller weighs 280 tons and is about 157ft wide and 66ft tall.
It works in a similar way to the MSS and the form traveller machines, acting as a movable concrete mould to complete the full deck width, which, at just over 143ft metres at its widest point, will carry six lanes of traffic.
The machine is fixed on two railway tracks that sit on top of the deck section that has already been cast by the MSS.
Concrete is poured into both sides of the machine at the same time, enabling workers to cast 40ft sections of the outer deck on each side of the viaduct.
Once the concrete has set, hydraulic jacks push the machine forward to the next position and the cycle is repeated.
Sixty-two concrete pours are needed to create the outer deck of the north approach viaduct, while 47 pours will take place for the outer deck of the south approach viaduct.
The first pour took place on Friday and each consists of around 2,825 cubic feet of concrete.
Once complete, the two elevated approach viaducts will stretch across the saltmarsh on either side of the river, connecting the Mersey Gateway bridge to the main road networks in Runcorn and Widnes.
Two wing traveller machines will be used on the project, one for each of the approach viaducts.
The main structure of the north approach viaduct is expected to be complete by the end of 2016.
Richard Walker, Merseylink’s project director, said: “This is a significant achievement for the project. The wing traveller is yet another piece of specialist equipment that has been developed to build the approach viaducts, which will link Halton’s iconic new bridge to the local towns and the wider region.
“This project is an immense task and one which we are on target to complete by autumn 2017.”