Engineers jack up Nuneham Viaduct and remove abutment

Network Rail engineers led by Balfour Beatty have jacked up Nuneham Viaduct and begun removing the southern embankment in preparation for the new abutment to be constructed.

Nuneham Viaduct is a bowstring truss bridge crosses the River Thames near Abingdon in Oxfordshire. The current bridge opened in 1907 and a new arched brick-built northern abutment was constructed in 1929. However, the southern abutment was not rebuilt and is now the cause of a problem that led to the structure being closed to rail traffic last month.

It was closed to trains in early April after Network Rail’s monitoring equipment detected unsafe levels of movement in the structure. The rail line between Didcot Parkway and Oxford is now expected to be closed until June as engineers are working around the clock to stabilise it.

The work has ramped up over the last two weeks, with Network Rail programme manager Claudia Philps explaining: “We have jacked up the structure and we’ve started the removal of the embankment and the structural abutment wall.” Around 3,000m³ of material has been removed from site already.

In the last couple of weeks, 24 piles have been driven 10 to 15m into the riverbed to hold up the temporary propping system, which was moved into place by a 750t crane. This is now holding up the bridge’s southern span while the old abutment is removed.

The bridge has been jacked up by over 700mm to bring into a horizontal alignment. “This has allowed us to start the demolition of the embankment and the abutment to allow us to continue the repair and the rebuild of the abutment,” Philps said. “Having jacked up the bridge, we’ve been able to expose the top of the [abutment] structure, the bearings, and now since the demolition of the embankment we’ve been able to get behind the structure. It’s incredibly solid in its construction and we’re working through removing it to enable the future construction [of a new abutment].”

This has been to prepare for the permanent piles for the new abutments. “Once we have completed the removal of the abutment, we’ll then start installing new piles along the same line in order to build the new abutment back up in the coming weeks,” Philps said.

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