Cable inspections on M48 Severn Bridge come to an end
A programme of cable inspections on the M48 Severn Bridge to monitor corrosion and ensure the bridge remains open and safe is now reaching an end.
Inspections have been taking place since June on eight sections across the two main suspension cables as part of a £5 million routine safety investigation by National Highways.
Inspections take place every six years when the main cables are wedged open allowing the team to see right to the centre and to assess the condition of the 53 wires inside.
Completion of the work by National Highways, working with contractors Amey and VolkerLaser, means that the cable inspection gantries and traffic management can now be removed.
To ensure the safety of workers and road users while this takes place, the bridge will be closed to traffic this weekend.
National Highways Project Manager, Chris Pope, said:
“Carrying out these essential cable inspection works will help us to keep the bridge safe and open for many years to come. They enable us to establish the current condition of the suspension cables and ensure the long-term viability and safety of the bridge.
“It has been a long and complex task to carry out this work and we have opened up over 900 metres of cables. We will need to complete some laboratory testing of samples and analyse the findings of the inspections but so far the results are in line with what we expected.
“We are now in a position to fully open the bridge once again and appreciate people’s patience during the closures which are essential to remove the traffic management and inspection gantries safely.”
The bridge will be fully closed to traffic from 7pm tomorrow (Friday 17 March) to 6am on Monday 20 March while the inspection gantries are removed by crane.
The eastbound carriageway will be closed from 7pm Monday to 6am Tuesday 21 March to remove the traffic management and fully open up the bridge to two lanes again.
Corrosion was discovered in 2006 in the bridge cables and measures have been undertaken to minimize any further corrosion. The inspections are carried out to monitor the cables and to ensure the levels of corrosion have not increased.
One of UK’s three, long-span parallel strand suspension bridges, the Severn Bridge has very small spaces between the 8,322 individual 5mm wires that form the two main cables. These small gaps allowed moisture to enter and cause corrosion.
The findings from the inspection will be shared once the full report is finalised.
All works are always subject to change depending on weather or other unforeseen circumstances.
Remarkable footage of the last inspection gantry being lowered can be seen here.