The bridge, north of Stafford, will be dismantled and the entire 150-tonne centre section lifted clear and taken away in one piece on a 90ft long specialist transporter to a nearby compound.
The work forms part of plans to improve journeys in this area by adding extra capacity and technology to the motorway.
Other sections of the Creswell Home Farm bridge will be taken away later. In total, the bridge contains enough concrete to fill 40 tipper trucks. The old bridge will be recycled and used in the construction of the upgraded motorway.
While work takes place the M6, between Stafford (junction 14) and Stoke-on-Trent (junction 15), will be closed in both directions for up to 24 hours from 8pm on the evening of Saturday 22 September. It will reopen on Sunday 23 September as soon as work is completed, and it is safe to do so.
The bridge is no longer in use and is too narrow for the upgraded motorway which will have an extra lane in each direction.
Highways England smart motorways project sponsor, Peter Smith, said:
Demolishing the bridge is a big and complex job and to do it safely both carriageways of the motorway are needed, meaning the M6 will be closed for up to 24 hours.
We’re doing all we can to minimise disruption. That is why we are arranging to take the centre section away in one piece, rather than breaking it up which would take more time.
I’d like to thank motorists, businesses and residents for their patience. I’d also urge anyone wanting to use the M6 in that area to plan an alternative route to avoid congestion between Stoke and Stafford. Please also allow extra travel time and fuel for your journey.
Traffic will be diverted off the M6 between junctions 14 and 15 and will use the A34 Stone Road as the diversion route. This route has been agreed with local authority partners and will be kept clear of other works during the demolition. Drivers are warned to expect delays and urged to avoid the area if possible, allowing lots of extra time for essential journeys.
To reduce M6 traffic on the day, signs will alert motorists to the closure as far away as Dover and Carlisle. Motorists and hauliers travelling between the North West and the Midlands and South of England will be urged to avoid the area by using the M62 and M1.
Work is under way with emergency services and social care providers to ensure they maintain their services along the route.
More information can be found on the M6 junction 13 to junction 15 smart motorway scheme web page.
Members of the public should contact the Highways England customer contact centre on 0300 123 5000.
Journalists should contact the Highways England press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.