PROTECTING AQUEDUCT FOUNDATIONS

Underwater foundations of aqueducts being dramatically scoured away by fast-flowing river currents have been protected with hydrographic survey equipment and divers in the River Eden in northern England

The foundations, in the River Eden, support three railway viaducts: a 1940s-built concrete structure, which in turn supports a railway that carries goods down the west coast and two viaducts, one of them Victorian.

Since the summer of 2021, the three structures have cost £5.1 million (€5.8 million) to be protected, which has been paid for by the railway firm Network Rail.

Using hydrographic survey technology, the river bed was scoured to show the true extent of the damage to the foundations, which is believed to have worsened during recent heavy rainfall.

Until the works were completed, trains were forced to run at reduced speeds of just 20mph.

“Due to working in the river, Network Rail worked very closely with the Environment Agency and Natural England to ensure construction methods had the least impact on wildlife as possible,” says Network Rail. “This included the development of a special mix of environmentally safe ‘non leach’ concrete, which was pumped underwater into the gaps of the West Coast main line structures by professional divers.

“Huge boulders (5,000 tonnes) known as ‘rock armour’ were also placed in the water to divert river flow around the viaduct supports – known as piers – at all three structures.”

In the later stages of the work, 4,000 tonnes of special setting concrete was poured, taking up a volume of 1,850m3.

“Now the winter rains are once again swelling the River Eden our vital work to protect the three railway viaducts is being put to its first big test and it’s great to see our improvements protecting rail passengers and freight trains,” said Rob Stephens, Network Rail principal route engineer.

“These projects have been challenging and have blended technological and engineering innovations alongside traditional techniques. Using new technology will be crucial as we make the railway more resilient from severe weather and our changing climate in future.”

Van Oord wins Scottish flood scheme deal

Van Oord is to construct a flood protection scheme for Millport, on the island of Great Cumbrae, Scotland.

Working with its subsidiary Mackley, Van Oord will improve the condition of the 2km long Millport seafront, making it more resilient to floods. The work will include replacing, reinforcing and constructing flood walls as well as installing offshore and shore-connected rock breakwaters.

“The Millport Flood Protection scheme will further protect properties and land on the islands,” said Councillor Scott Davidson, Cabinet Member for Place of North Ayrshire Council.

“It is also important in an economic sense as it will allow us to pursue our ambitious plans for the new marina,” he added.

Van Oord has completed a number of similar coastal protection schemes in the UK, such as at Lydd, Dymchurch, Hythe Ranges and the adjacent Broomhill Sands on the south coast of England, as well as the construction of the South Breakwater of the new Aberdeen South Harbour.

“Our project team is looking forward to working closely with North Ayrshire Council, the local community, and other stakeholders in order reduce flood risk at Millport,” said Paul Hesk, managing director of Van Oord UK.

Jumbo Offshore has completed a highly skilled precision lifting job involving transportation and wet storage of a riser caisson for Technip FMC.

The job saw Jumbo deploy its heavy-lift vessel Fairplayer to handle the 120-metre long and 1.3-metre diameter caisson.

“This job involved the careful handling of fragile offshore equipment. But with our experienced crews and engineering teams, combined with the dual cranes of the Fairplayer, Jumbo Offshore had the technical capabilities and offshore expertise that made this precision operation a success,” said Carol Granneman, project manager, Jumbo.

“Technip FMC is a very valued client of ours and we look forward to working with their team in the future.”

Finely-tuned

The Fairplayer picked up the caisson from the Scottish port of Nigg, an operation that demanded a finely-tuned rigging arrangement due to the high flexibility of the caisson.

To this end, each of the Fairplayer’s 900-tonne cranes used double slings and a total of five connection points.

After transporting the caisson to the offshore location, Jumbo then executed the