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Richmond July 2016
Approximately 300 m of 2.5 x2.5 x 1.8m Fibreglass Culvert liner was installed from one access point approximately midpoint along the project.
The installation of 300 m of fibreglass culvert pipe liner inside an existing concrete box culvert looked very self contained to the average pedestrian...except for what looked like a long row of Beige looking porta-potties or Fibreglass shower inserts lined up along the West side of Number 1 road.
The Fibreglass Culvert liner was only available from the middle east and was ordered months earlier and shipped to the job site at Number One road and Westminster highway in Richmond. Once the pipe arrived a few pieces of equipment showed up and a few generation plants were set up for reliable power for air fans to circulate the air into the Existing (host) culvert pipe.
This was a long and involved process and started with the complete crew being trained in confined space rescue and safe working techniques. Very few excavations were dug. The South and North ends of the project had an excavation and trench shoring cars to allow for an entrance into the Host pipe. An opening was cut into the existing "host" culvert for entrance and egress from the Host culvert pipe as well as air being pumped into the work space inside the host culvert pipe.
The midpoint of the 300 m was excavated and trench shoring cages were introduced to stabilise the ground and provide an entrance point for the new fibreglass liner pipes. This was a much larger excavation and the top of the existing box culvert was completely removed. This provided space for the lowering of the assembled fibreglass liner pipes to be inserted into the Host culvert pipe.
Once the entrance and exit point were completed, an assessment and cleaning of the culvert was completed. A small "skid steer" loader was lowered into the existing culvert and scraped the gathered debris on the floor all the way to each end where a vacuum truck extracted the debris.
Once cleaned a set of "rails" were constructed out of 2 inch "box steel" and welded together to allow a stable and "on grade" platform for the Fiberglass culvert liner to be installed and room for concrete to be pumped into the void for structural integrity.
The fibreglass liner pipe is shipped as tops and bottoms standing upright on pallets. The pipes must be assembled and the two parts of the pipes are "snapped' together to form a waterproof bond and then gaskets are applied to the spigot end. Many assembled pipes are then drilled and ports are installed to allow for the grout to be pumped in place once installed.
A special forklift was used to moved the new fiberglass pipe into place and they were installed with a tight fit with gasket bell and spigot type connections. Throughout the job holes were cut into the fibreglass pipe to allow for the service laterals from the houses storm water service as well as the existing Catch basins along the curbs.
Short pieces of pipes were attached to the existing pipes and then grouted into the Fibreglass pipes to allow the concrete to be pumped into the void at pressure without it entering into the fibreglass pipe liners.
Once installation of the fibreglass liner pipes was finished a careful placement of concrete allows for support of the fibreglass liner and a very long lasting Box culvert with many decades of service.
Installing liner pipes acts like a concrete form inside the host pipe allowing for a virtual new pipe to be installed using the structural strength of the existing pipe. Some of the benefits of this process is the lack of disruption to the neighbourhood as well as cost savings. Traditional open cut replacement would require many months of excavation and material being trucked off site as well as the removal and dumping of the concrete box culvert in place.
This method was not only quicker, more cost effective, but also had a much lower carbon footprint. Along with the few truckloads of material excavated and trucked to a dump site and a similar amount of clean fill brought back when the excavation was filled there were just a few concrete trucks used to pump concrete to fill the void, very few trucks were involved in the project.
This new method of pipe rehabilitation was proved a success and PW Trenchless is looking forward to using this technology again in the future.