Fish Creek Tunnel
Fibre Reinforced Shotcrete Tunnel Lining
Barchip Fibre Reinforced Shotcrete helps contractor The Wesson Group deliver $1.8 million in saving and reduce tunnel lining thickness by 50%.
Constructed by hand in the early 1900’s, the 1.6 km long Fish Creek Tunnel is an integral part of the city of Rome’s drinking water supply. After 100 years the tunnel was starting to show its age, with several rockfalls noted along the length of the unlined tunnel. In 2015/16, repair works were undertaken to remove tunnel debris and install a modern fibre reinforced shotcrete support lining. The project used a BarChip fibre reinforced permanent shotcrete lining, which was delivered via a surface borehole and pumped through 1000 m of steel and rubber lines of approximately 2 inches internal diameter. Completed in 2016, the project was named Winner of the 2016 New York State Chapter of the American Public Works Association Statewide Environmental Project of the Year. BarChip delivered many benefits to this small but technical project.
BarChip Delivered an 88% Decrease in Fibre Volume
The original design called for a dose rate of 100 ld/yd3 of steel fibre reinforced shotcrete which negatively effected shotcrete workability. BarChip was able to meet the performance specifications with just 12 lb/yd3, allowing for a standard mix design with great workability.
BarChip Enabled a 50% Reduction in Lining Thickness
The original design called for an 8 in thick lining applied in two passes. The first a 4 in thick pass with 100 ld/yd3 of steel fibre. The second a 4 in thick unreinforced pass to protect the inner lining from corrosion. However, BarChip fibre does not suffer from corrosion and was able to meet the performance requiremet with a single 4 in thick lining dosed at 12 lb/yd3.
BarChip Reinforced Shotcrete Passed Water Quality Testing
The Fish Creek Tunnel is an integral part of the City of Rome’s fresh water supply and as such must pass NSF64 water certification testing. Due to anti-corrosion admixtures, the steel fibre mix was unable to obtain certification. The Barchip reinforced lining did not require additional admixtures and passed NSF64 water testing.
BarChip Helped Deliver c.16% Cost Reductions
Contractor The Wesson Group LLC, working with engineers GHD were able to deliver the project $1.8 million under the $11.2 million contract price. The reduction in lining thickness and time saved in applying the lining were some of the main contributors to these savings.