The speed with which the damaged M1 bridge could be repaired may depend on what steel parts are in stock, an expert said this week.
If the steel needs to be replaced, the repair time will depend on how quickly steel work with the necessary dimensions can be made available.
“That steel work needs designing and installing and certification,” said Mott MacDonald project manager Chris Atkins.
“It’s not really practical to expect someone to keep reinforcements around just in case,” he
However, if the steel reinforcement does not need to be replaced, repairs could be made in as little as one week, he said.
The concrete beams can be reinstated with spray concrete fairly quickly, with three or four days then needed for the concrete to harden, said Atkins.
Hydro-demolition an option
Before applying the spray concrete, engineers would have to remove the damaged material, perhaps by using hydro-demolition to break it up, said Sandberg Consulting Engineers partner Mike Eden.
However, until a full engineering assessment is made, the possibility of severe damage that requires a full re-build of the bridge has not been ruled out.
The damage could go much deeper than is apparent to the naked eye, or equally it might not go beyond the spall zone [what is visible], said Eden.