RamArch
Interested in learning more about how RamArch can enhance your project?
Project: Whiteball Railway Tunnel Refurbishment – RamArch.
Owner: Network Rail.
Designer: Donaldson Associates/OTB Engineering.
Contractor: AMCO.
Purpose: Strengthening of a brick-lined railway tunnel lining.
RamArch Type: Plain steel 8mm RamArch mesh, manufactured to BS standard.
RamArch Finish: Galvanised & later fully encapsulated in shotcrete.
Date: RamArch installed late 2011, Shotcrete completed 2013.
Whiteball tunnel is located on the Paddington to Plymouth main line near Taunton in Somerset. The 1095 metre long, twin-tracked railway tunnel was constructed by I K Brunel in
1842. The tunnel was constructed to his original broad gauge and consequently the tunnel profile is unusually large.
The tunnel has suffered through weathering, water ingress as well as a sulphate attack over the 160-plus years of continual operation. This had lead to degradation of the mortar joints and delamination of the brickwork.
Network Rail’s standard tunnel repair methods were continually being carried out. However, the rate of deterioration was such that a completely new approach was needed. The RamArch system was selected as the method of carrying out the repair works. This is because it provided a safe method of working and rapid installation times.
On this project it was fixed in position by using 200 mm long bolts, set in place using high-speed fast setting resin, although there are other systems that could be used.
The design called for further bolts to be fitted around the periphery of the arch again using fast setting resin to form a very robust structure.
ISS developed and manufactured an erection frame system that enabled the safe and rapid assembly of the RamArch sections on the ground that were then lifted into place using a telehandler in order for the tunnel refurbishment to proceed.
Six areas of the tunnel were treated totalling 355 linear meters over 6No, 48-hour abnormal T3 weekend possessions enabling the line to return to high speed operation. The installed RamArch offered intimate support to the tunnel lining as well as completely eliminating the problem of falling brickwork. This was risking the safe running of the operational railway.
Sometime after the RamArch installation a second 3-day blockade was ordered to complete all of the spray concrete works within the blockade to form the permanent steel reinforced concrete lining.
Interested in learning more about how RamArch can enhance your project?