The crew at PW Trenchless were up in Squamish to replace a sewer main under highway 99 via Pipe Bursting. On November 15, 2022, the first burst of 135 metres took place along Mamquam Road towards Highway 99. The exit pit was dug close to the intersection of Mamquam Road and Highway 99.
The site was not suitable for using a pair of trench shoring cages so the removal of the large pipe bursting head was a bit more complicated and required some extra excavation once the burst was completed. The burst went smoothly and the 135m of pipe were inserted via Pipe Bursting in roughly 3.5 hours.
Of course there was quite a bit of set up before the burst was started. For this project, it was decided to excavate around two manholes and jackhammer out the benching and channels of the base of the manholes. This allowed the burst to continue through the two manholes unimpeded, allowing for just one launch of the bursting tool for this 135 metre run. The two manholes had trench shoring cages supporting the excavation as well as a few spots where the existing infrastructure was excavated to make sure the bursting head could pass without causing any problems.
The entrance pit was 4 metres deep so the large diameter 450mm HDPE pipe had to have a long sloped entrance ramp excavated to allow the pipe to enter the host pipe without any grade, allowing the grade of the host pipe to be unaltered.
The HDPE pipe was fused together and there was a large lay down area on the side of the road by the golf course that was not in any vehicles or pedestrians way. There was a bypass pump system put in place and various additional pumps were set up to ensure the excavations were kept dry for the duration of the burst.
On the day prior to the burst, the pulling apparatus was put in place and the pulling rods were inserted into the Host Pipe. The pulling cone was installed on the lead end of the HDPE pipe. The morning of the burst it was moved across the road and put in alignment with the host pipe.
The pumps looked after any existing ground water in the excavations, but luckily it was a dry sunny day. The weather was a bit cold and once the Replacement pipe was staged into the entrance pit it was discovered that the swivel that connects the Bursting head to the pull back rods had a small amount of ice in the cavity. The swivel was hung above the exhaust of one of the nearby generators that were powering the bypass pump and the ice was removed.
Once the head, swivel and pull back rods were attached, the crew took a well deserved coffee break and the burst commenced before 11a.m. The crew was diligent watching the inspection pits to make sure the bursting head and pipe went under the existing infrastructure without damaging any existing pipes.
The site was wide and traffic was only stopped a few times while excavators needed to be moved to align the pull back rods when the swivel and head were attached and then to move a generator to all the vacuum truck better access to remove debris from one of the pits.
The length and depth of this sewer main made it a perfect candidate for pipe bursting, and saved approximately 560 Tonnes of material or 40 truck loads of material from being excavated out of a trench for open cut replacement of this pipe. Unfortunately the section of pipe under the Sea to Sky highway has had some repairs in the past so, pipe bursting that section is still being looked at as a possibility.
This was a 120 metre burst and was the longest of the three burst in this project for the Township of Langley. Working on 200th Street has it’s challenges but the work went smoothly and traffic control was important to the completion of the job. The pulling rig has the capabilities of pulling up to 430,000 lbs or 215 tons. The pressures for this pull were never very high. The rig only came with 123 m of pulling rods so the entrance pit had to be elongated to allow the pulling head to be inserted close enough to the pulling rods.
City of Langley
200th and 50th
Sewer upgrade from 8″ 200mm to 16″ 450mm
Numerous runs and a few open cut section to replace over 300 m of pipe and manholes. The section are over 4 m deep and 200th is an extremely bust thoroughfare.
March 29, 2021
The city of White Rock had a sewer main that needed replacement just up from the west end of the beach with the exit pit was just west of the intersection of West Beach Avenue and Anderson Street. The run was west on West Beach Avenue and many house were located along the street making for a tight situation for the lay down area for the fuse sections of HDPE pipe. The best situation was to fuse the sections into two runs with a final fuse of the section done just prior to the burst.
8:50 a.m. The rods were inserted into the host pipe and sent up to the exit pit.
10:14 a.m. the rods entered the entrance pit. While the rods were being installed, the steel plates that had been securing each of the service laterals were removed. The two sections of the HDPE pipe were moved into place and the pulling head was installed onto the East end of the HDPE pipe. The pipe was then staged at the entrance pit waiting to be attached to the pulling rods.
10:21 a.m. the Pulling head was attached to the rods.
10:24 a.m. The new HDPE pipe enters the host pipe
10:33 a.m. The pulling head enters the first of the Service lateral connection pits
10:35 a.m. The pulling head enters the first of the gas service connection inspection pits. No problems with excess soil. No contact was made with the gas service line.
10:40 a.m. The pulling head enters the second of the gas service connection inspection pits. No problems with excess soil. No contact was made with the gas service line.
10:49 a.m. The two sections of HDPE pipe are fused together without interrupting the pipeburst in progress. The fusion machine is one wheels and can easily roll with the pipe being inserted.
11:20 a.m. a gas service had been previously excavated for observation while the pulling head was going past the gas service. A large amount of the material had to be dug by hand to clear the soil that had been pushed into the excavation by the pulling head. The Gas service was left intact.
11:31 a.m. A Steel Robar type repair couple had to be cut away from the bursting head. This was only done to ensure clearance for upcoming gas and water service connections.
1:07 p.m. Another Steel Robar type repair couple had to be cut away from the bursting head as it came into and service lateral connection pit.
1:40 p.m. The pulling head reached the Exit pit (Pulling pit) Approximately 140m of pipe installed in 3 hours and twenty minutes.
10 city blocks of sewer were replaced on a steep street in the City of West Vancouver in late spring of 2019. Starting at the Clive Avenue and going up the hill to Mathers, the complete sewer was replaced.
Special challenges on this project were the numerous schools and parks within the project’s area. Traffic was managed but many residents learned quickly to drive over to either 12th or 14th Street. Road plates were used over the excavations when school was letting in and out for the safety of the children walking to school.
Although the host pipe was not deep it was on a severe grade and bursting downhill is easier on the equipment. To minimise the amount of exit pits, a few times two burst were completed using the same exit pit by sending the pulling rods straight through an existing manhole and doubling up the length of the run for the rods. The pipe was pulled through the higher Host pipe and then another section of pipe was attached at the manhole midway and inserted into a second entrance pit.
This was the final part of the contract that was started in 2017 with 5 of 8 Sections completed by PW Trenchless starting in 2015. This project was also the first time PW Trenchless had tried to replace a 200mm pipe with 450mm pipe, an upsize of 2.5 Times the flow for the pipe. This was certainly in the experimental stages for this type of upsizing and the pipe was fairly new PVC which although still having many serviceable years left, the increase of population density was overwhelming the pipe.
A special cutter was used to split the PVC pipe to aid the burst. A bentonite lubricant was also used to lessen the friction of the ground surrounding the pipe and was pumped into the interior of the new HDPE pipe and inserted into the void right behind the bursting head. The head was also comprised of three piece including two various sizes to compress the surrounding material as well as the cutter.
The first sections were burst through Kanaka Creek park and PW Trenchless was very concerned with environmental conditions including high water levels and the presence of the public visiting the park. The park was not closed at any time due to the work performed by PW Trenchless.
Maple Ridge Alley
In the early part of 2019 PW Trenchless replaced a sewer for the city of Maple Ridge in a narrow laneway parallel to Lougheed highway. The project was complicated by the tight setback of buildings that in some case were right up to the property line.
The depth of the existing sewer ruled out open cut construction as an option and the entrance exit pit in the center of the project was extremely complicated to excavate. A soils Engineer was brought in to document and access the ground conditions to ensure the safety of the crew and the success of the pit.
Liberal use of trench shoring cages by Direct Equipment West Limited allowed for the pits to maintain open for the duration of the project even if heavy rains came. Staging of the pipe was done within the footprint of the job as no driveways or entrances were on the south perimeter of the job.
The fall and winter of 2019/2020 was again a time for PW Trenchless to completely measure and prepare 2 sections of pipe within the Radium Hot Springs park area for the installation of Glass Reinforced Plastic pipes inside two Culverts in Radium Hot Springs just North of the Hot Pools. Both had roadways on top of them and the crew had to install the pipe sections in the winter when the flows of the Sinclair Creek are at the lowest.
The longer of the two sections was just North of the Radium Hot Springs pools and the other section was a few kilometres up the Banff-Windermere Highway. The project uses Glass Reinforced Plastic (GRP), supplied by Chaneline International. GRP is a precast segmental liner which allows for, after a meticulous measuring process, each section of GRP to be hand formed and specifically designed for a particular location in the host pipe before being shipped to site.
This meticulous measuring was accomplished by a team of PW Trenchless technicians who spent many days inside of the host pipe made of deteriorated Corrugated Steel. When the pipe was delivered to the site, PW Trenchless Construction had already set up the By-pass pump systems and cleaned out the host pipe to make way for the new sections of pipe.
The pipes were installed on steel channels welded to the bottom sides of the Host pipe and once all the pipes were installed, concrete was pumped into the void between the host pipe and the outside of the new Glass Reinforced Plastic. The outside of the Glass Reinforced Plastic is coated with a rough material to further enhance the bond between the new concrete filling the void for further strength of the completed pipe structure.
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).
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 MoreIn 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 MoreThe 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 MoreOften 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 MorePipe 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 MoreHorizontal 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.
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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.
