The scope of work encompassed the rehabilitation of approximately 380m of 36″ (914mm) diameter steel water pipeline for the Douglas Rd. Main No. 1 section, from Delta Ave. to Beta Ave. in Burnaby BC. The selected method of rehabilitation was Slip Lining with 30″ (762mm) diameter High Density Polyethylene (HDPE) DR9 pipe with grouting of the annular space between host and carrier pipe. A thick walled pipe (DR9) was necessary to handle the high operating pressure of the GVWD watermain. Residents were afforded the ability to utilize the front entrances to their properties at all times during construction and retain the use of street parking where deemed necessary, highlighting one of the major benefits of trenchless construction – A Less Invasive Process Compared to Traditional Methods.
Eagle Creek Culvert in West Vancouver was experiencing severe failure along culvert invert which could potentially cause above ground failure. The project was determined to be high priority due to close proximity residential properties that had been constructed on the slop directly above ground. PW was able to complete structural rehabilitation works safely, efficiently and cost effectively (at a fraction of the budget anticipated for a traditional open cut method).
The City of New Westminster has been one of the first municipalities in British Columbia to recognize its aging infrastructure. They have assessed all of their underground assets and adopted a more advanced program of pipe rehabilitation than any other city in B C. We have been a part of that program, off and on, for the last 18 years – In fact, we have been part of their pipe replacement program and this is one example of the types of projects we have completed for the city.
Because the city is densifying, the sewage flows have increased dramatically. An example of this is in the area of 6th street, where a number of bursts were completed to rehabilitate an existing sewer main that was not adequate for the quantity of flow. Along with replacing the mains, the new apartments in the vicinity had to be kept online, while the work was progressing. A system of bypass pumps were used to facilitate the sewer outputs from the apartments. Some service laterals were replaced via pipe bursting as well. The project started from a manhole on the very busy 6th Street and progressed North Eastwards for a number of manholes.
In 2012, a section of trunk sewer pipe that was failing in Richmond needed to be replaced. Because of the close proximity of a block, building conventional well pointing was not advised. We decided to use ground freezing to stabilize the ground to allow the bursting operation to take place. Ground freezing is a common process in New York for building excavation and it is also used in mining and tunnelling. Its use in utility installation is rare. We employed Canadian Dewatering and Wier Jones Engineering to design and install a system of wells, with pipes carrying a recycling coolant driven into the ground using techniques borrowed from the well pointing installation processes.
A refrigeration plant was brought on site and coolant was circulated via a closed looping system. This was done around both manholes, one at each end of the pipe needing replacing. The centre of the frozen zone was excavated down to the pipe, and the pipe burst was accomplished with no danger to the surrounding buildings. There was no movement of groundwater, resulting in no building movement or migration of ground pollutants in this industrial area.
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During the fall of 2017, PW Trenchless replaced AC water mains via Pipe Bursting on the Simon Fraser University Campus adjacent to Terry Fox Field. The existing alignment ran in parallel proximity to the newly laid state-of-the-art running track, any damage caused to this surface would have necessitated the replacement of the whole thing! Pipe bursting removed the need for heavy machinery to excavate along the entire length and therefore mitigated the risk of damage to the track. All track & field activities were permitted to proceed as planned, with the exception of moduloc fencing deployed to protect crews from wayward lacrosse balls, while the target pipe was discretely replaced under feet.
A prime example of the less invasive nature of trenchless construction in action. Intricate work zones accurately positioned throughout densely tree-lined streets allowed for the replacement of deteriorating sewers. Up-sized to exceed current capacity requirements, providing results long into the future, this major construction process was able to be performed while simultaneously preserving not only the trees themselves but even their delicate blossoms.
The King George Highway was opened a year after King George’s Royal Visit to Canada in 1939. He planted trees alongside the highway in South Surrey and over time these have become part of the community. When the underlying sewer pipe needed to be replaced, Pipe Bursting was chosen because of concerns over damage to the root structure which would result from choosing open cut pipe replacement processes.
The existing 350 mm pipe was replaced with 650 mm HDPE pipe. This experimental burst did cause some heaving to the grassy area and also to some of the curbs. This was one of the first large upsizes of pipe attempted by PW Trenchless Construction Inc.
The Highway 99 Oak Street Bridge project is a classic example of our signature process — “The Culvert Way” . For a deep dive click here.
Not all Bursts are long sections of pipe needing replacement, and PW Trenchless can easily handle these smaller jobs efficiently.
The section of pipe connecting sewer mains in a Surrey neighbourhood was initially installed in a pipe easement between four house lots. There was no need to upsize, as the flows had been consistent since the area had been developed in the early 1960’s. However the existing pipe that was used was Asbestos Cement. This product can have issues loosing its cement and becoming “mush’ resulting in pipe failure. Pipe Bursting offers a great solution to the replacement of these pipes.
In the case of this particular site, the trees had grown in size along with new installations of concrete walkways, fences and structures, making open cutting this sewer cost prohibitive. To complete this project, a pit on the south side of the property line, straddling two properties, was excavated to be used as the entrance pit. The exit, or pulling pit, was excavated on the boulevard on the northern edge of the road on the north edge of the project. The new pipe was then pulled in and the old pipe “bursted” into the surrounding ground and replaced .
This project was completed quickly, with little to no disruption to the homeowner’s property.
Throughout the 1950’s and 60’s the City of Richmond had a program of infilling their ditches with large cast-in-place box culverts. These concrete culverts are in great shape but their joints are failing. Over the years this has caused continuous road surface failures and the city has entertained various solutions to solve the issue. In 2016, a contract was initiated by the City of Richmond specifying that a FRP lining product be installed. PWT, seeing an opportunity to be the frontrunner, bid on this job and was the successful tender. This allowed us to be the first to install GRP in BC in a Sliplining situation.
To complete the process we took a section off the top of one and half sections of the existing box culvert to allow an entry point for new sections of glass-reinforced fibreglass sections of pipe liner. The liner product was custom made in Dubai for this project.
The existing sewer needed to be fully cleaned and prepared by PW Trenchless technicians who all had completed confined space rescue training. Along with the insertion of 330 meters of 2500 mm by 1200 mm pipe, all service connections needed to be reinstalled to the new liner. Upon completion of the liner pipe installation, concrete was pumped into the void between the existing host pipe and the new liner.
An alternate tendering process where the contract is awarded to one entity which comprises both engineering and contracting.
Because PW Trenchless Construction offers such innovative solutions for underground utilities, it is often beneficial for the owner to request solutions based on a performance specification. This allows PW Trenchess to offer unique solutions while working with equally innovative engineering companies.Learn More
New installation methodologies include HDD & traditional open cutLearn More
In this day & age of pipe systems reaching the end of their projected lifespan, pipe replacement and pipe rehabilitation have become major fields of engineering.
PW Trenchless Construction provides viable options such as pipe bursting, loose fit lining and internal pipe re-construction whether partial & fully circumferential.Learn More
The aging culverts under roads and highways in many case have reached the end of their engineered life-span. We consider the rehabilitation or replacement of these culverts to be vital to our built environment.
PW Trenchless has been a pioneer in working with MOTH, railway companies and municipalities in developing rehabilitation methodologies for the hundreds of thousands of culverts that currently exist in BC. We have offered solutions in both procurement and construction from design-build to sliplining, invert rehabilitation and full circumferential relining.Learn More
Often pipe failure can be concentrated to one section, for various reason, leaving the rest of the pipe in good condition. The repair of these localized failures are know as external point repairs (EPR's).
EPR's demonstrate PW's ability to work as both a trenchless and civil contractor, completing EPR contracts using our civil contracting skills and assisting other pure trenchless contractors who only have the capacity to work in an existing pipe.Learn More
Pipe upsizing is the fundamental concept of pipe bursting.
The vast majority of pipes are less than or equal to 200mm in diameter, but with today's densification practices of urban design, there is a major demand to increase current capacity to handle extra flow. Pipe bursting provides the ideal solution to this issue, particularly in an urban setting .Learn More
Horizontal Directional Drilling is a low impact Trenchless construction service where pipe is installed in a shallow arc along a bore path which has been created by a drilling rig. Often the terms Horizontal Directional Drilling (HDD) and Directional Boring are used interchangeably, but in our industry we use the word “boring” when we utilize smaller sized drilling rigs with small diameters for short crossings in the hundreds of feet, and we use the word “drilling” when we utilize larger rigs with large diameters for long crossings in the thousands of feet.Learn More
When you join PWT, you become part of a community of people who are engaged in the most innovative practices in the Trenchless Industry. We have been instrumental in setting up a scientific method for cities to gain carbon offsets/credits from their use of trenchless construction. This system has been reviewed by the BC Government and has been approved as of December 2018. We expect to see it in common use shortly.