Dashcam footage posted on Facebook shows the moment a 100 tonne platform crashes 60 feet to the ground underneath the M60 at Barton Bridge in Salford.
The video has already been shared over 1,500 times.
No one was hurt when the huge structure collapsed on Monday 16 May.
But workers who witnessed the crash told SalfordOnline that it was lucky no-one was killed.
Video posted into this Facebook group about demolition and construction shows a lorry driver driving towards the building site, near the Trafford Quays leisure complex.
60ft bridge collapse at Barton bridge Trafford! The moment the structure gives way caught on video 16/5.
Posted by Wiganers on Thursday, May 19, 2016
The platform starts to swing and is slowed by safety cables before smashing to the ground in a cloud of dust.
Eyewitnesses on the scene said it ‘sounded like an explosion’.
Deep gouges were cut in the four huge concrete pillars that make up this new lifting bridge when, it’s assumed, steel cables holding the platform in place failed.
The £30m Western Gateway Infrastructure Scheme, which is due to provide a new dual carriageway over the Manchester Ship Canal, is a joint scheme run by Buckingham Group Contracting and Hochtief (UK) Construction Ltd.
Work started in May 2015 and was supposed to be completed by July this year.
