May 2021 Vol. 76 No.5
Features
Trenchless Employs Latest Auger Boring Tech for Parallel Drainage Project
Under a busy patch of highway between Mead and Loveland, Colo., an auger boring crew for BTrenchless recently completed a drainage project to support the area’s expanding population. The team installed a pair of 200-foot parallel, 42-inch steel casings under the highway to connect drainage ponds on each side of the road using an auger boring machine outfitted with a McLaughlin On-Target Steering System (OTS).
While this type of work is pretty standard for BTrenchless, Director of Business Development/Estimator Chris Knott and Project Manager Matt Wojtkiewicz used the job to compare two different types of casings and maximize their crew’s productivity.
The Henderson, Colo.-based underground specialty company, BTrenchless, has a 41-year history performing trenchless work across the western half of the U.S. From auger and guided boring to tunneling, pipe bursting and ramming, it handles the challenging large-diameter work that can’t be done with horizontal directional drills (HDD).
“The owners of our parent company, BT Construction, saw a lack of trenchless expertise in the region for the type of work we do,” said Knott. “So, they heavily invested in all of the latest and most innovative equipment for this type of work, hired a lot of smart, hardworking individuals, and demonstrated a commitment to ongoing education opportunities for everyone on the team. The business took off from there.”
Planning the parallel bore
With so many trenchless methods at his disposal, Knott’s task is to determine the most effective way to complete a job. For this parallel drainage-line highway-crossing, he narrowed his options to two: a pilot tube system or the OTS system.
“The bores were shallow, going from one ditch to another,” Knott explained. “The soil under the road was silty sand, so we had some concerns about what potential voids using a pilot tube system with drilling fluid may cause.
“Also, using a pilot tube system would have almost doubled the amount of time on the job, and we would have had to add a couple of additional workers pulling rods on the exit side. Those extras can impact the cost-per-foot of a job.”
Wojtkiewicz added that another advantage of the OTS System, when working in sandy soils over a pilot tube system, is its ability to recess the cutting head into the OTS head to avoid overcutting the loose material and creating a void ahead of the casing.
“Luckily, the ground material stayed consistent on these bores, and we didn’t have to do that. But it’s nice to know that option is available in ground conditions like the one on this project,” he said.
After choosing the best installation method for the project, the team at BTrenchless set the stage to compare the two different types of steel casing products.
For the first bore, the crew welded and installed 5/8-inch Trinity spiral weld steel casing in 20-foot sections at a time. On the second, BTrenchless used the Tri-Loc weldless interlock casing system, a new product from Trinity.
“The Tri-Loc system has a bevel outer edge that helps with alignment. Sections of pipe are secured using three rows of interlocking teeth,” explained Tony Baker, business development manager for Trinity Products. “On auger boring jobs, that usually means aligning the next section of pipe in the pit with a crane or excavator, and then advancing the auger boring machine until they hear the ‘popping’ sound of the teeth locking together. It can all be done in a fraction of the time of traditional welding methods.”
BTrenchless’ objective in using the two different casings was to compare how much faster the crew could complete the bore using the Tri-Loc product compared to having to weld together each section of pipe.
“The soil conditions were the same. We used the same auger boring machine equipped with the same McLaughlin OTS head. And the people on the crew were the same. So, it truly was a fair comparison,” explained Knott.
Comparing productivity
On the first bore using the standard spiral weld pipe, the crew was able to complete the bore in seven working days, averaging about two hours of welding every time a new section of pipe was added.
Using the Tri-Loc product on the second bore, the same crew was able to double the production per 10-hour shift, to finish it up in a little over three days. The crew even tack welded each joint for added peace-of-mind.
“We typically use a five-person crew on auger boring jobs, and anytime a new section is being added to the pipe string, three of them are waiting around for the welding to be completed,” said Wojtkiewicz. “So, cutting that idle time by approximately 75 percent is huge for our customers and us.”
The team at BTrenchless prides itself on keeping up with all the latest advances in trenchless technology. In fact, it first learned about the McLaughlin OTS System at the Underground Construction Technology (UCT) International Conference & Exhibition a few years back, and more recently, the Tri-Loc product at a microtunneling training event.
“Before investing in the OTS System, our crews were making our own steering heads that could be adjusted for grade,” said Knott. “But we didn’t have anything to check and adjust the line like the OTS does. We rented the system a couple of times before investing in our OTS control station and various sized steering heads.”
After running the numbers from the parallel bore drainage project, Knott and Wojtkiewicz plan to use the Tri-Loc pipe and the OTS System on future projects, as well. “For thicker, larger-diameter pipe, this can be a cost saver for our customers and will help our team stay productive.”
These two labor-saving technologies helped BTrenchless complete this project’s second bore in short order and provide a great solution on future projects.
FOR MORE INFORMATION:
BTrenchless, (303)-286-0202, btrenchless.com
Vermeer MV Solutions, (888) 837-6337, vermeer.com
Trinity Products, (800) 456-7473, trinityproducts.com
Underground Construction Technology (UCT) International Conference & Exhibition, uctonline.com
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