Blog

May 28, 2023

Approval granted for refurbishment of Tyneside’s Grade I listed High Level Bridge

Gateshead and Newcastle Councils have given the green light to Network Rail for

Gateshead and Newcastle Councils have given the green light to Network Rail for a £4M package of refurbishment works to be carried out on the High Level Bridge across the River Tyne.

Constructed between 1845 and 1849, the 408m long structure was the world's first combined road and rail bridge, with the railway above the road to minimise its width. It was designed by Robert Stephenson as a crucial link in the rail network to Scotland and was opened by Queen Victoria on September 28, 1849. It received Grade I listed status in 1950.

Having previously undergone refurbishment works in 2001 and 2008, validation inspections undertaken by Aecom say that once again repairs are needed to correct a number of defects on the bridge. Some of these are longstanding and have been previously noted, but a number of new issues have been identified too.

Fractures in the cross bracing have long been a problem on the bridge, with many previous repairs visible. The new set of repairs will include over-plating new fractures with steel angle sections resin bonded to the cast iron. This bonded repair detail technique was used in the 2008 refurbishment, but there is some concern about the long-term sustainability of this method because some have "fallen off" since then. Network Rail proposed using this technique in conjunction with countersunk bolts that cannot be seen.

There is longitudinal cracking in one of the longitudinal trough girders at rail deck level in the south approach structure. One crack was noted in 2016 and a second was identified in the same girder in 2019. It is proposed that a bonded plate is installed over it.

Water seepage through the deck has been identified as far back as 2014. Aecom did a detailed inspection of the soffit in July 2022 and found that water seepage had damaged the paint system to all cross girders. Some coating loss was in excess of 1000mm and there was around 2mm of corrosion loss to the bottom flanges. These defects were centred around the interface between the timber decking and the precast concrete parapet plinths, which has led engineers to conclude that there is a consistent issue with the water seepage at the interface between the timber deck and the parapet plinths through all spans.

Defects on girders of High Level Bridge

The inspection also discovered that a significant proportion of the clamps attaching the deck timbers to the cross girders were loose, while the clamps at the deck ends were also badly corroded.

A full blast clean and repaint of all cross girders is part of the proposed works, but only steelwork installed as part of the 2008 refurbishment. Corroded and loose deck connection brackets will be repaired as required.

The bridge's waterproofing system will be renewed. Sub-surface drainage is being considered but may also "cause weakness in the system as water could get in from the ends of the bridge". It is possible that the road bridge's original drainage system, which runs through the concrete upstand, would remove any water that gets to the road surface.

According to Network Rail, the package of works will repair the defects and remove any risks associated with the structure. Simultaneously, the works will have a positive impact upon the appearance of the structure.

The work will begin this summer and last around seven months. Network Rail is working to minimise disruption and will ensure that the bridge remains open to all vehicles during the day. It will close to road traffic at night.

In its approval of the works, Gateshead Council said "future longevity of the structure, as well as improve public safety" would be ensured.

Newcastle Council added: "Whilst there will be some minor visible alterations to the bridge structure as a result of the repairs, it is considered that the harm (less than substantial) is outweighed by the public benefit in this case, both in terms of the ongoing preservation of the Grade I listed heritage asset and enabling its continued use for trains and other vehicles."

The six-span bridge, mainly made of cast or wrought iron, was constructed by Hawkes, Crawshay & Co of Newcastle. It has previously undergone extensive refurbishment projects in 2001 and 2008, which strengthened the structure and restored some of its original features. The latter programme of works won the 2009 Grand Prize for Conservation from Europa Nostra due to its research into the use of cast iron and the conservation techniques used.

Like what you've read? To receive New Civil Engineer's daily and weekly newsletters click here.