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Sanders Utility Construction, Inc. of Charlotte, North Carolina, is installing 20,000 linear feet of hi-capacity 48 in. steel spiral water main pipe, in 50 ft. joint lengths.
Shoring the installation of such long pipe is no easy task. Sanders is utilitzing a long in-line trench shielding system that incorporated two “trained” trench shields, with abutted hi-clearance spreader arches.
Each trench shield is a custom-built HDHT8 model with sidewalls measuring 8 in. thick and 10 ft. high. Pin-in-place spreader arches with 60 in. cross beams are set at the adjoining ends of each box to allow greater clearance for the pipe joints.
“We’re real pleased with how the boxes are working,” Says Project Superintendent, Steve Sanders. “We’re getting very good daily pipe production, and the shields are working exactly the way we expected them to work.”
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The Charlotte-Mecklinburg Utility recently let an $9.6 million bid to install 20,000 linear feet of hi-capacity 48 inch steel spiral water main pipe, in 50 foot joint lengths. Taking on the challenge of installing the behemoth sticks of pipe over that long run is Sanders Utility Construction, Inc. of Charlotte, North Carolina.
“Before we started the project, we debated on whether to install 25, 30, or 50 foot lengths of pipe,” says Freddie Young, Project Manager for Sanders Construction. “Because so much of this pipeline is going cross country, from a production aspect the most cost-effective options was installing 50 foot joints as much as possible.”
Shoring the installation of such long pipe is no easy task. To build one trench box to accommodate that length would require extremely hi-capacity machines just to move the trench shield.
Sander's contacted Safe-T-Shore--a subsidiary of trench shielding & Shoring manufacturer Efficiency Production, Inc.--about custom shoring options.
Mike West, Safe-T-Shore’s Vice President of Engineering, came up with a plan for a long in-line trench shielding system that incorporated two “trained” trench shields, with abutted hi-clearance spreader arches.
Explains West: “We finalized a custom-designed system that combines a 34 foot and a 30 foot long trench boxes into one 64 foot modular unit. The boxes can quickly and easily be put in and pulled out of the trench as the pipe installation progresses, and it doesn’t require extraordinarily heavy equipment.”
Safe-T-Shore “Super Arch” trench boxes save the day
Each trench shield is a custom-built HDHT8 model with sidewalls measuring 9 inches thick and 10 feet high. Pin-in-place spreader arches with 60 inch cross beams are set at the adjoining ends of each box to allow greater clearance for the pipe joints. The outer ends of the two trench shields are equipped with 7 foot spreader pipes.
“We’ve actually built a couple of these ‘Super-Arch’ boxes for other projects that have needed the extra length for long pipe installs,” explains West. “In each situation, the contractor has been very happy with the trench shields, and they have worked very well.”
Sanders agrees, “We’re real pleased with how the boxes are working. We’re getting very good daily pipe production, and the shields are working exactly the way we expected them to work.” Sanders recently ordered two more Safe-T-Shore trench shields to be primarily used for installing the pipe at greater depth, where stacking the trench shields is the optimal technique for shoring.
The average depth of the new watermain is between 12 – 16 feet. About 60 percent of the pipeline runs across country, with 40 percent installed in the right-of-way of existing roads. In places, Sanders uses only one trench box to install 25 ft. joints of pipe.
This pipeline installation is part of the Charlotte Utilities’ Southwest Watermain Project, Phase B-1 project. When completed, the new transmission main will provide continued capacity to the city-wide water distribution system.
The Right Tools for the Job
Undoubtedly, heavy machinery is necessary to manage the pipe installation and the two-shield combination, so Sanders is using a Komatsu PC750 and Komatsu PC400 excavators.
Founded in 1997, Sanders Utility Construction Co., Inc. employs over 40 people and are capable of handling any water, sewer, or storm drain project. They are recognized as one of the leading utility contractors in Mecklenburg, Cabarrus, and Union Counties.
Safe-T-Shore provides trench shoring equipment developed and engineered for the safety and productivity of the underground construction industry. Safe-T-Shore Trench Shields are P.E. certified to assist with compliance of OSHA requirements. Contact Safe-T-Shore at 800-380-0103.
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