Piling work on the extension of the M74 in Glasgow has been halted after a crack was found in the city’s subway system.
Subway operator Strathclyde Partnership for Transport (SPT) on Friday said it would not consent to more piling work on the £445M M74 extension until it is satisfied more problems will not arise.
The 8km extension to the M74 is being built to cut congestion on the busiest stretch of the M8 through Glasgow by the Interlink M74 Joint Venture, which comprises Balfour Beatty Civil Engineering, Morgan Est, Morrison Construction and Sir Robert McAlpine.
The crack was found on the ceiling of the subway in a tunnel adjacent to West Street station during overnight inspections carried out for SPT in the early hours of 5 March. Debris was also found falling from the crack.
Bored cast in-situ piles were being installed for the foundations of the M74 extension 23m away from the subway when the crack appeared.
“Engineers at SPT are now working alongside the contractors to ascertain the cause of the crack,” said an SPT spokesman.
“We will not allow piling to continue until we can guarantee that our tunnel’s integrity will not be affected.”
A spokeswoman for Balfour Beatty said that piling would continue elsewhere on the project, but would be monitored closely.