Part of Brighton, Colorado’s successful formula for growth is a sound infrastructure that provides businesses with access to up-to-date facilities and services. The city has taken steps to upgrade and expand its infrastructure to attract new businesses to the area. One project involved the expansion of a 24-inch water distribution line in a quadrant bordered by Colorado Highway 85 and E-470 located within the metropolitan Denver area close to Denver International Airport. Extending the water line required passing under Highway 85 and a Burlington Northern railway. This portion of the project required some planning as the highway and railway were adjacent to each other, and the area included an existing array of telecom, fiber, gas, sewer and water lines. To add another layer of difficulty, the ground conditions consisted of sand, gravel and clay. When the project went out to bid, Northern Colorado Constructors knew they had the equipment and expertise for the job.

Planning pays big dividends

The project called for a 36-inch casing, which would house a 24-inch water main, to be installed under Highway 85 and the Burlington Northern Railway. The total length of the bore was approximately 700 lineal feet. As Chris Zadel and his team reviewed the project, they decided trying to complete the full bore in one shot would be difficult. The project required precise placement of the casing both vertically and horizontally to avoid the existing infrastructure and a house that sat within 20 feet of one of the receiving pits.

“We took our time with the planning stage, but we wanted to be proactive due to the tight requirements and traffic flows in the area,” says Zadel.

After taking into account the ground conditions and precision placement, NCC decided to place the bore pit in between the highway and railway and complete two bores — one 340-foot bore under the highway and a second 340-foot bore under the railway.

“We were concerned the ground conditions may limit our ability to effectively complete a 700-foot bore and we had a slight deflection into the receiving pit on the far side of the railway,” says Zadel. “We figured the chances of losing material in front of the head were high and that could potentially affect the structure of the highway; plus, hitting that mark in the receiving pit would be easier with a shorter bore.”

New technology comes to the rescue

Due to the ground conditions and precision needed to hit the receiving pits, Zadel decided to try a new steering head. The ON-TARGET steering head from McLaughlin allows contractors to control horizontal on-grade changes and lateral direction changes. The new system provides more control of the auger boring steering head for more accuracy for difficult on-grade bores.

“We felt the ON-TARGET steering head offered us the capabilities we needed and kept the material tight in the front of the steering head, so we wouldn’t lose the material as we were boring,” says Zadel. “The ON-TARGET steering head worked great and we hit our marks with no issues.”

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