Civil: Lamington Viaduct Emergency Repairs

Lamington Viaduct Emergency Repairs

Location: Lamington, UK

Lamington Viaduct is located around ten miles south of Carstairs on the West Coast Mainline.

On the morning of December 31st 2015, after the torrential weather of Storm Frank, a train driver reported a dip in the track over the viaduct. In response, a temporary speed restriction (TSR) was imposed pending the arrival of track maintenance staff who, after examining the track and watching a train pass over the viaduct observed unusual track movement – a few minutes later the line was blocked.

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Site

Lamington Viaduct is located around ten miles south of Carstairs on the West Coast Mainline. On the morning of December 31st 2015, after the torrential weather of Storm Frank, a train driver reported a dip in the track over the viaduct. In response, a temporary speed restriction (TSR) was imposed pending the arrival of track maintenance staff who, after examining the track and watching a train pass over the viaduct observed unusual track movement – a few minutes later the line was blocked.

The extent of the underwater damage to the bridge was not immediately apparent on the 31 December. After river levels had fallen further, a photograph of pier two taken on 1 January shows a single sandstone block missing. As this was at the top of a pyramid further missing blocks would only become apparent from a diver’s inspection.

The following day, a diver from Subsea ROV & Diving Services inspected the piers. His report showed the damage to be far worse than expected. Below the waterline most of the masonry pier’s sandstone blocks had been washed away.

The Project

AMCO (Amalgamated Construction) who has both the framework and emergency response contracts for structures in Scotland with Network Rail was mobilised on New Year’s Day 2016. By 3 January, work had started on an emergency haul road to deliver material for the repair of the Viaduct

Solutions

Pier two took the brunt of storm Frank’s record water flow. Its permanent repair required a reinforced concrete jacket on either side of the pier designed by Donaldson Associates. Each jacket had a footprint of 21m x 2 metres and would rest on the concrete poured to secure the viaduct. The jackets would be fixed into position by 125 x 8m R38 hollow soil anchors, 75 on the south jacket and 50 on the north.

Result

Train services resumed running over Lamington Viaduct Monday 22 February.
A seven week engineering project, which involved diverting the Clyde and stabilising the structure, saving it from collapse was completed two weeks ahead of schedule and without any accident or incident.

Lamington viaduct’s last annual detailed inspection was in June 2016. This included an examination for scour by divers which revealed no issues.

Acknowledgements

Minova wishes to thank Amalgamated Construction for their support and permission to publish this case study.