Contractor W.W. Clyde goes deep down the street with help from Efficiency Slide Rail from United Rentals

A 60 in. diameter welded-steel pipe is not typically the type of utility buried as much as 19 ft. deep in the road at the end of your home’s driveway. This ain’t no hydrant tap. It’s the creation of the Point of the Mountain Aqueduct (POMA); the installation of 68,500 linear ft. of a new drinking water pipeline that will run approximately 12 miles through the heavily residential and suburban communities of Draper and Sandy, Utah, near Salt Lake City.

The ability to lay the pipe without having to close down access to entire neighborhoods is made possible with the help of a unique, custom-engineered shoring system: a Linear Slide Rail Bay System manufactured and designed by Efficiency Production, Inc., a leading trench shield and shoring manufacturer headquarter in South-Central Michigan.

Point of the Mountain Aqueduct Project
Construction of POMA began in March 2005 and when complete in 2007, will deliver water to approximately 500,000 residents in the Salt Lake Valley. The pipeline will connect two water treatment plants, one of which–the Point of the Mountain Water Treatment Plant–is also currently under construction; and establish a critical link between the valley's major water distribution systems.

POMA is one of the Metropolitan Water District of Salt Lake & Sandy’s (MWDSLS) most significant undertakings in 50 years for the Salt Lake Valley area. “The Point of Mountain Aqueduct and new treatment plant will assure that we meet all of the water needs for the Salt Lake Valley communities,” says Robyn Clayton, spokesperson for the Metro Water District: “We have seen tremendous growth in the area, and we are trying to be proactive to make sure water needs are met not only for the present, but for the future as well.”

Choosing the Right Contractor for the Job
In December 2004, MWDSLS awarded the $64 million project to general contractor W.W. Clyde & Company of Springville, Utah. Founded in 1926 by Wilford W. Clyde, the company has constructed interstate highways, bridges, dams, airports, mines, golf courses, environmental reclamation projects, large site work/preparation, and other types of large construction projects in the Intermountain West.
Selecting the Right Shoring System

One of the first challenges facing Allan Schieb, Clyde’s Construction Manager for the POMA project, was choosing an appropriate shoring system for the pipeline. Initial recommendations were to utilize traditional steel trench boxes, however the extreme length of pipe being installed (44 ft. per stick) would require job-specific trench boxes at least 50 ft. in length. Trench shields of that size are very heavy and difficult to handle with even large trackhoes and equipment, and have limited future utilization.

Schieb looked at every factor possible in choosing an appropriate shoring system: soil conditions throughout the route of the pipeline; geotechnical reports; and the locations of the many existing utilities including water, sewer, irrigation, gas, and telecommunications. When his research was completed, Schieb knew that a Slide Rail System would be the best option due to its:

• Usability to accommodate an un-obstructive open trench of significant length and duration with the use of external walers and sacrificial members.
• Ability to facilitate the excavation of deep trenches in heavily residential and urban areas, while requiring less space and work area than other shoring systems.
• Ease of installation of the system’s smaller, lighter components.
• Ability to work in a linear fashion over great distances, similar to trench shields.

Efficiency Production Slide Rail System Passes the Test
The final question to answer was which Slide Rail System to choose. “I talked with as many people as I could about Slide Rail including shoring manufacturers, other contractors, and equipment rental businesses,” said Schieb. “Eventually, I chose an Efficiency Production Slide Rail System because in the final analysis, it was just a little bit better than other systems,” Schieb added.

Additionally, the personnel at United Rentals-Trench Safety in Salt Lake City had experience with Efficiency Production Slide Rail, and their assistance on the project was also a determining factor for Schieb. “I had never used a Slide Rail System before and the sales staff from United Rentals were available at any time to help explain the concepts of the system and how to install it,” says Schieb,

Efficiency Production’s Director of Engineering, Mike West, never doubted that Efficiency could design, engineer, and manufacture a system that would meet all the shoring challenges of the POMA project. “After looking at Clyde’s specs, I quickly realized that not only would Slide Rail work, but that it’s the best system for this application,” explains West. “The pipes are extremely long, and Slide Rail allows the trench to be open and properly shored for extended periods of time, but also allows the trench to be unencumbered by cross braces or I-beams when installing the pipe by using external walers and sacrificial members.”

Why Slide Rail Works in Tight Quarters
Efficiency Slide Rail is a component system comprised of steel panels and posts. The system is installed simultaneously as the trench or pit is excavated by pushing the posts and panels down to grade as the pit is dug; a process commonly referred to as a “dig and push” system. The stackable panels slide into rails in the posts, either a double or triple rail, depending on needed depth. In a linear or “bay” configuration, 1ft. wide parallel beams slide into the inside of linear posts and pin-in-place standard trench shield spreader pipes as cross members – an innovation that increases the systems compatibility. With the use of external walers and sacrificial timber, the parallel beams can be removed to lay oversized pipes.

The Linear Slide Rail System makes it easy to cut right along streets or other existing structures in tight right-of-ways and easements while continually providing a safe and properly shielded work area for pipe installation crews. It’s the difference between needing to close several entire roads; or just a part of a road, leaving at least one lane of traffic available.

Slide Rail, Shore-Trak Tandem Conquers Cross Utility Challenges
As Clyde’s crews progress through the suburbs and residential areas, they are encountering many cross utilities which slow their progress. Clyde is addressing the shoring needs around existing utilities by utilizing Efficiency’s Shore-Trak system, which includes steel panel guide frames with narrow steel panels that slide down through the frame and pin-in-place before they touch the existing utilities.

Shore-Trak is the industry’s only pre-fabricated, pre-engineered cross trench utility system designed to work in combination with Slide Rail. Shore-Trak guide frames have tracks which connect into the Slide Rail posts, completely integrating into the linear-bay system. Schieb comments: “The Shore-Trak component has really worked well; it is doing exactly what it is supposed to do.”

Slide Rail’s Pros and Cons
With a project of this magnitude, there is a steep learning curve for contractors and engineers who have never previously used Slide Rail. For Clyde, the biggest challenge was improvising with the system when the pipe changed directions or needed to curve slightly. Schieb adds, “It just takes time and practice before becoming proficient using the system. My crews are experts at laying pipes, and it has taken time to become comfortable with installing and moving a shoring system.”

Clyde currently has six crews installing pipe simultaneously in different locations along existing easements through residential neighborhoods in Sandy and Draper, Utah. Each crew includes a superintendent, foreman, three operators, and five laborers; utilizing about 250 feet of shoring equipment. Equipment includes two large 365/375 Caterpillar trackhoe excavators, and a medium Caterpillar 330 trackhoe. To dig inside the shoring, the operators are using smaller 1.5 and 2.75 yard buckets on their machines. Much of the initial pip installation occurred last summer, and Clyde is positioned to move quickly this year as the weather gets better.

“Despite the system’s challenges when the pipe changes direction and that my crews have needed a lot of technical support to learn how to install it, the Slide Rail System really has done what’s it’s supposed to do,” Schieb comments on the system’s advantages and disadvantages. “It’s very well built–overbuilt really–and everyone is always very safe laying pipe. It’s a total shoring system,” Schieb adds.
 

W.W. Clyde & Company, the general contractor on the POMA project, is shoring the aqueduct pipeline trench with Efficiency Production Inc.’s Linear-Bay Slide Rail System. Each of Clyde’s six pipe installation crews has 250 ft. of Slide Rail posts and panels configured in 24 open bays, the longest linear-bay application ever designed and engineered!

A linear slide rail application allows pipe to be installed deep in a trench that’s cut entirely vertical with absolutely no sloping. In the heavily residential area of Salt Lake City’s suburbs, slide rail is the difference between needing to close entire roads, or only one or two lanes of traffic.

As Clyde encounters various cross-trench utilities; they are utilizing Efficiency Production’s Shore-Trak system, which completely integrates into the Slide Rail System. Shore-Trak features 2 ft.-wide steel panels that slide through a guide frame and pin-in-place around the cross utility pipes. Shore-Trak is the industry’s only pre-fabricated, pre-engineered cross trench utility system designed to work in combination with Slide Rail.

With the use of external walers (top left and right) secured to the slide rail’s linear posts with large c-clamps, plus sacrificial timbers at the bottom of the trench; the parallel beams and spreader pipes can be removed and the trench left open to accommodate the installation of the oversized 44 ft. long sticks of 60 in. diameter welded-steel pipe.