The Mersey Gateway project passed a huge milestone today, as the two sections of deck linking the North Approach Viaduct to the north pylon deck span were joined together.
This is the first of four deck joins, called key segments, that will take place this summer.
In total there are five sections of bridge deck and approach roads that need to be joined before the River Mersey is fully bridged, and the deck of the Mersey Gateway Bridge is completely joined up.
The new bridge deck is being built in three separate sections, with the deck being built outwards from each of the three pylons at a rate of around six metres per week.
As well as being linked to each other, the north and south main bridge deck sections also need to be linked to the approach roads – the viaducts built over the saltmarsh and the canals – approaching the river.
Hugh O’Connor, General Manager of Merseylink, said completing the first bridge key segment marked an historic moment for the project.
“We have now linked the sections of deck together by bridging the gap between the two decks with four steel restraint struts that resemble giant bolts and a concrete pour,” he said.
“Once the concrete has set, the decks are further locked together with external post-tensioned tendons.
“The combination of the concrete, steel struts and external tendons mean the structure can bear hundreds of tonnes of force, helping to hold the bridge in place.
“This is a major step for the project, and we remain on target to complete the final three joins this summer, with the bridge expected to open to traffic this autumn.”
Forty cubic metres of concrete were used to fill the 2m gap between the North Approach Viaduct and north pylon deck span, and the pour took around two hours to complete.
“We could only complete the pour once the form traveller was moved into position and the mould had set. The gap between sections was only two metres wide, but runs the entire 32 metres width of the bridge deck,” Hugh said.
“Around 18 hours after the pour, the concrete sets to full load-bearing strength.”
The final three deck joins are expected to be completed over the summer months, with the bridge on course to open this autumn.
Cllr Rob Polhill, Leader of Halton Borough Council, said: “Joining the first sections of the bridge deck together is a fantastic achievement.
“There are now just three more joins to make between the different sections of bridge deck before it runs continuously across the estuary.
“If you haven’t done so already I would urge residents to get down to the riverbank to see the work that has been achieved.”