Bridging the gap

29 Dec 2009

by Ewan Fergus, The Herald

Early in the new year massive sections of bridge will be inched into place to carry the M74 sweeping over the main West Coast rail line at the Port Eglinton viaduct.

The operation, part of the massive M74 Completion Project, will be a painstaking affair. Each of the 170-metre 4,000-tonne steel segments has to be edged into place at a speed of just 10 metres per hour.

The process is a delicate one, because the railway line beneath must remain open throughout.

That means the work can only be carried out in the wee small hours, for just two hours a night.

Despite the constraints, Transport Scotland are confident that, like the rest of the project so far, the work will be caried out on schedule.

The viaduct is just one of the many jobs that have to be done to join the M74 to the M8 in Glasgow, and complete the "missing link" in Scotland's transport network.

The scale of the project is massive and includes the construction of 13 bridges and one underpass, but work is now developing at speed.

At Fullarton Road, two bridges are being constructed and should be going up in February, while the Auchen-shuggle Bridge, taking the M74 over the Clyde, will be manoeuvred into place in June.

One of the most complex parts of the plan is being carried out at Rutherglen Station, where both carriageways of the M74 will cross the railway lines either side of the station itself and over a section of the station platform.

The four-span bridge is supported at each end by re-inforced concrete supports and at three intermediate locations by re-inforced concrete columns. The bridge deck will be made up of steel box girders with re-inforced concrete cast in place over them.

The steel girders will be lifted into position over the railway lines during the night when the rail lines are closed. Commuters using the station will be unaffected by any of the bridge work.

Stephen McFadden, engineering representative on the M74 project, said: "Piling work at Rutherglen Station is underway and the bridge beams will go up in February.

"The bridge supports are concrete, and we have to pile into the ground to build them.

"The steel beams of the four-span bridge are being fabricated in Darlington at the moment and we should be moving them into place in February or March.

"It's quite tricky because there is a live railway line here, and we cannot have any impact on it, so all the work there has to be carried out at night.

"We're piling in between the lines at the moment, and that has to be done with care. It's complex work."

But despite the project's complexity, it is expected that the whole M74 link will be open, on time, by August 2011 at a cost of about £445million.

Graham Porteous, head of construction at Transport Scotland, says it will have a massive impact on the efficiency of Glasgow's road network, reducing congestion and making journeys easier and faster.

Mr Porteous said: "The M74 link will remove congestion for people who currently find themselves sitting in queues of traffic on the M8 at rush hour in the morning.

"It will provide an alternative route to the south west and it also opens up the development potential for the south of Glasgow, with direct motorway access.

"Overall, it will open up a range of regeneration opportunities for the whole of the west of Scotland."

However, the project has also been throwing up other benefits as it progresses.

Pupils from Cairns Primary contacted Transport Scotland to say they were interested in learning about the environmental impact of the project.

To help pupils get a close-up view of the work without putting themselves in danger, a viewing platform was built close to the site where the Auchenshuggle Bridge is being built.

Mr Porteous added: "There's been a lot of engagement with classes.

"The kids were interested in the river and from our point of view it helps us make them aware of the project and construction generally."

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Reproduced with the permission of the Herald and Times Group.

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