RamArch
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Project: Clay Cross Railway Tunnel Stabilisation
Owner: Network Rail
Designer: Donaldson Associates & Innovative Support Systems
Contractor: AMCO
Purpose: Stabilisation of a brick-lined railway tunnel lining crown arch
RamArch Type: Plain steel 8mm RamArch mesh, manufactured to BS standard.
RamArch finish: Galvanised
Date: Late 2013/Early 2014.
The 1.6km-long Clay Cross railway tunnel in Derbyshire, now part of the Midland Main Line Network, was constructed by George Stephenson and completed in 1839. Over its 170-plus years of continual operation, the tunnel has been subjected to weathering, water ingress, and sulphate attack, leading to the gradual degradation of the mortar joints and delamination of the brickwork. These issues posed significant risks to the tunnel’s structural stability, necessitating a comprehensive programme of stabilisation works.
In 2013, a project was undertaken to address the structural concerns in the tunnel, particularly focusing on its crown. The RAMARCH system was selected for this work due to its proven capability in stabilising aged and compromised tunnel structures. Several areas of varying lengths along the tunnel were targeted for reinforcement, each requiring precise planning and execution to minimize disruption to rail services on this vital transport route.
One of the key challenges was ensuring that the RAMARCH system provided intimate contact and positive support to the intrados of the existing brick lining. To overcome this, ISS developed an advanced mechanical expansion system. This innovative solution allowed the prefabricated arch sections to be erected and positioned on steel lintels anchored securely to the brick lining. Once in place, the expansion system enabled the arch to be precisely adjusted, ensuring a tight fit with the existing structure. This intimate contact was crucial for effective load transfer and long-term stability.
After expansion, the arch was permanently anchored in place, providing robust and reliable support. This approach not only restored the structural integrity of Clay Cross railway tunnel but also extended its operational lifespan, preserving this historic engineering feat for future generations. The successful implementation of the RAMARCH system at Clay Cross demonstrates the vital role of modern engineering techniques in maintaining and rehabilitating heritage infrastructure while meeting the demands of modern transportation networks.
Interested in learning more about how RamArch can enhance your project?