Terra Nova Tunnel Liner Plate Extension
Due to the high costs of replacing failing infrastructure, interest is growing for the rehabilitation of existing steel and concrete structures in a variety of different geometries. Relines with Tunnel Liner Plate offer superior solutions because they are often constructed more quickly than other building alternatives, can provide significant cost savings in locations where structures have a high amount of ground cover, and cause the least amount of disruption to the general public.
In the Fall of 2012, Armtec was asked by Public Works Canada to visit a site in Terra Nova National Park in Eastern Newfoundland and assess the possibility of rehabilitating a 47-year old structure, installed in 1965 using Armtec Multi-Plate. At the site meeting it was determined that a rehabilitation with Tunnel Liner Plate would be the right solution and aluminum plate was selected because
of the long service life it would provide. Because of its location at the bottom of a steep embankment, accessibility to the existing culvert was a challenge.
The portability of the product made it a great solution for the unique geography of the project. Tunnel Liner Plate, which only Armtec
manufactures in Canada, could be shipped to the site and hand-carried in segments weighing only 9-14kg through the length of the existing host structure for erection. The alternative choice would have been to incur significant construction costs in building the access infrastructure, which could also negatively impact the park’s environmentally sensitive area.
After Public Works Canada determined that Tunnel Liner Plate would be most suitable for the installation, Armtec’s engineering team quickly prepared a detailed set of drawings and specifications for Public Works Canada to review. In the summer of 2013, a tender was called for the work which included Armtec’s drawings and specifications in the tender package.
As the only manufacturer of Tunnel Liner Plate in Canada, Armtec’s Newfoundland team secured the business in late 2013, began
installation of the structure in May 2014, and completed the project the following month. The work involved relining the existing 2,430mm diameter Armtec Multi-Plate which was installed under 8m of cover with a new 2,250mm diameter Aluminum
Tunnel Liner Plate.
During construction, the site was visited by a number of parties such as Engineering Consultants, Department of Transportation Engineers, and Public Works Engineers. Given the unique challenges posed by the project, there was tremendous interest in Armtec’s solution, so much so that one worker proposed (tongue-in-cheek of course) charging every visitor a toll to see the project!
Feedback from visitors to the site was overwhelmingly positive and Armtec’s products generated a substantial amount of interest. The installation of Armtec’s Aluminum Tunnel Liner Plate was a successful project for Public Works Canada and caused little disruption to the visitors of Terra Nova National Park. More importantly, there was little environmental impact to the area. To learn more about this project or for more information on Armtec’s various Tunnel Liner Plate options, please speak with an Armtec
Representative or visit our website at www.armtec.com.
- 10″ pump at upstream end, allowed Multi-Plate to be completely dewatered.
- Existing Multi-Plate was cleaned of all debris and rocks.
- Plates were placed in bundles at upstream end of culvert by excavator.
- Plates were brought into the structure by hand, according to plate layout per ring.
- Crew of 3 assembled 5 plates inside structure. Final top plate was then put into position to complete the first ring.
- 2×4 was used as blocking to ensure uniform spacing and proper alignment.
- Second ring was assembled with 5 plates and moved into place next to first ring. Once in place, final top plate was placed into position. Each ring was bolted to the previous ring through an inward projecting vertical flange. This allowed assembly to be completed from inside the host structure.
- After three days, crew of three was able to complete 20 rings per day.
- Once all rings were completed, bolts were tightened to the specified torque of 115-135 foot pounds.
- Grouting was completed using a portable concrete pump. The grout mixture was a freely flowing mixture with an approximate 6″ slump that was pumped through 2″ grout plugs located throughout the structure. Grout was placed in 3 uniform lifts along both sides of the pipe while ensuring the design diameter of the reline pipe was held at all times.
- Grout was injected into the grout ports and the ABS plug was secured to prevent the grout from flowing out.
- Sand bags were placed around the structure inlet and outlet ends to prevent grout from flowing out at the ends.
- Plate Weight: 9-14kgs
- Ring Width: 500mm
- Total Rings Used: 87