National Highways is warning drivers and fleet operators to plan their journeys to avoid delays along the M3, which will be closed near Bagshott in Surrey this weekend, to allow a footbridge to be installed.
The Bagshot Heath footbridge, which crossed the motorway between junction 3 (Lightwater) and junction 4 (Frimley), was demolished in 2023, after engineers found issues with its ability to withstand crash impact from over height vehicles.
This weekend, a replacement structure – which weighs nearly 100 tonnes, is 63m long and 4m wide - will be lifted into place.
The motorway will be closed for the whole weekend – with the southbound entry slip roads closing at 12pm on Friday July 11 before the whole northbound carriageways shuts at 7pm and the southbound at 9pm.
The motorway will then reopen in both directions by 6am on Monday July 14.
During the closure, drivers heading northbound should leave the M3 at junction 4, follow the A331 north, then the A30 heading east and the A322 heading south, before rejoining the M3 at junction 3.
Those travelling southbound should follow the same diversion route in reverse.
The structure was originally due to be installed in April, but the work had to be delayed due to the concrete in one of the bridge abutments not hardening as expected.
The concrete has since passed subsequent tests and therefore is now safe to install.
Once the bridge is in place, contractors will need to fit mesh and anti-climb measures before it can be used by the public.
This work will be carried out during a series of overnight closures on the M3, before the footbridge is formally opened for use later in the summer.
Nick Axford, National Highways project manager, said: “We know how important this footbridge is to the community, and how disappointed people were when we had to postpone its installation, so we’re delighted to be taking a huge step towards opening it once again.
“Putting the bridge together has required sourcing several bespoke parts, which often take months to manufacture.
“For the installation to be carried out safely, we need to close this section of the motorway across the weekend.
“We acknowledge there may be some disruption as a result, but we are grateful to drivers for their patience and urge them to plan their journeys in advance.”
