Cable inspection work will keep M48 Severn Bridge open and safe for years ahead

Monmouth's MP has given his seal of approval to National Highways’ cable inspection work on the M48 Severn Bridge, which will halt corrosion and ensure the bridge remains open and safe for years to come.

David Davies toured the bridge to see how the £5m project inspecting several sections of the two main suspension cables ensuring corrosion is under control and the cables remain in good condition.

National Highways, along with contractors Amey and VolkerLaser, have inspected six out of the eight separate inspection panels on the bridge, including three at a high level using inspection gantries and three at a low level using scaffolding platforms.

Inspection of a seventh panel is currently in progress and the team will be starting the final inspection shortly.

Chris Pope, project manager for National Highways, said: "It was a delight to welcome David on to the bridge to showcase how we are ensuring this vital link remains open and safe for years to come.  

“Built over 55 years ago, the M48 is a crucial route across the River Severn and it is imperative we maintain it long into the future. 

“The inspections allow us to understand the current condition of the suspension cables and confirm that the measures we implemented over the last 15 years have been effective in ensuring the long-term viability of the bridge and the safety of its users.”

Mr Davies said: “I was pleased to see the good progress being made on the bridge, despite some of the adverse weather the team has faced over the last few months.

“The monitoring and mitigation of the corrosion on the cables will ensure this vital transport link between South Wales and the South West of England will remain open and safe for years to come.”

One of the UK’s only parallel strand bridges, there are very small spaces between the 5mm wires that form the bridge cable that allowed moisture to enter and cause corrosion.

The 511mm diameter main cables are opened up and inspected every five years.

Carried out in three phases, inspections will be focused on the lower central area of the suspended cable midway along the 988-metre-long main span of the bridge.

Cables are also being checked at the upper levels using two specially designed gantries that were installed using a crane and under a full closure of the bridge.  

To carry out these cable inspections and to ensure the safety of both the public and workforce, long-term lane closures are currently in place.

The inspection works have involved the closure of one lane westbound from June and one eastbound from July, with the works set to come to a close this March, weather dependant.

During the period of lane closures, vehicles over 2.9 metres wide will be prohibited from using the M48 Severn Bridge, and the bridge will also be closed totally over one more weekend to enable the removal of high level inspection gantries.

The final full closure is planned for March, weather permitting, with motorists being diverted across the M4 Prince of Wales Bridge.

To minimise any future disruption, maintenance work will also be undertaken during the closures, including refurbishment and maintenance of many bridge expansion joints, carriageway surfacing repairs, reinstatement of some under bridge gantry bogies and wheels, sweeping and litter picking, blasting and painting of parapets and lighting column bases, weld repairs, carriageway inspections, and gulley and drain cleaning.

Scott Millar, account director at Amey, added: “The regular inspection programme of the M48 Severn Bridge is critical to ensure local communities and the public can travel safely.

“With our inspection, design and operations expertise, we understand the complex design of the bridge and the time needed to inspect the bridge thoroughly. We recognise that road closures can be frustrating for local residents, but we’re pleased that the programme is on track to complete this year.

“We were delighted to welcome David today, to demonstrate the complexity of the bridge and the current inspection works, which is vital to keeping his constituents moving and connected.”

A full weekend bridge closure was due earlier in the year to remove the lane one closure on the eastbound side, but this is being pushed back to March 2023.

Work will continue to take place on both the eastbound and westbound cables from now until the completion of works.