A 2,500t section of the bridge deck was pulled 120m across the river in a 10-hour operation. The section is now resting on a series of temporary supports, enabling the second phase of deck assembly to get under way directly behind it on the south side of the river.
Hydraulic jacks were used to manoeuvre the steel frame to a temporary resting point a third of the way across the river. The current overall length is 230m, made up of 186m of permanent deck together with a 37m temporary nose and a 7m temporary tail. The first section of deck is made up of about 1,150t of steel and 212 precast concrete units weighing a total of 1,350t. A further 458 concrete units will now be added complete the length of the deck.
The launching operation went well said Stephen McCaffrey, project director of FVB joint venture, which was formed by Farrans Construction and Victor Buyck Steel Construction to deliver the project on behalf of Sunderland City Council. “Pulling a 2,500 tonne section of bridge out over the middle of the river is not easy and takes a lot of engineering and preparation,” he said.
The centrepiece 105m-high A-frame pylon will arrive on site this winter. Once it is in position, the extended deck will then be pulled across the width of the river ready for the cables to be installed.
Patrick Van Severen, project director for Victor Buyck Steel Construction, said: “This kind of bridge deck launch operation is always very exciting for our team because it is one of the major landmarks in the construction process, where people can see the scale of the project.
“We’re on track to open the new bridge in spring 2018 and our focus over the next few months will be on constructing the second phase of the bridge deck and bringing the pylon to Sunderland and then raising it in the river, which will be a spectacular sight.”
The design team is led by Buro Happold Engineering and Roughan & O'Donovan.