A stretch of the M6 in Cheshire that was closed after a defect appeared on the Thelwall Viaduct has reopened.
There were severe delays as engineers carried out emergency repairs to several grid plates which became loose and lifted out on to the road.
An expansion joint which mitigates against movement "failed", Highways England said.
The closure at junction 19 has been lifted and one lane has reopened at junction 20, motorway police added.
Two lanes will remain closed between junctions 20 and 21 for ongoing repairs.
The carriageway had been shut since 13:00 BST between junctions 19 and 21, causing "severe traffic in the area", police said.
Driver Terence McGuire tweeted that he had spent almost four hours in the queue.
Police tweeted "a huge thank you" to the public for their patience.