A consortium of six Green Bay, WI, suburban communities recently let bids to build a 65-mi. long raw-water pipeline from Ledgeview, WI, to a treatment plant on Lake Michigan in Manitowoc, WI.
The huge pipe-installation project is divided into separate contracts, where each contractor is responsible for installing sections of the pipeline in different locations along the path which runs through portions of Brown and Manitowoc counties.
Contract “I” was awarded to low-bidder PTS Contractors Inc., of Green Bay. The $11.6-million contract involves installing 46,000 linear ft. (14,021 m) of hi-capacity 48-in. (122 cm) steel spiral water main pipe, in 50 ft. (15 m) joint lengths.
Installing the very large, very long sticks of pipe over a long distance presented a number of shoring challenges for PTS. Company President Greg Joski, Vice President Mark Schleis, and Project Manager Steve Horn considered a number of options before contacting Justin Samuels at Miller-Bradford & Risberg, a leading distributor of trench safety equipment in Wisconsin.
“One of the first things Justin and I did was visit a few job sites and see what other contractors are doing in similar situations,” said Schleis. “Justin came up with a great plan that I think improved upon what others were trying.”
Samuels reviewed the project specs and contacted Efficiency Production Inc., a leading manufacturer of trench shields and shoring, headquartered in Michigan.
Efficiency Production has a strong reputation for custom engineering trench shielding systems to meet shoring challenges.
Samuels and Efficiency Vice President of Engineering Mike West, came up with a plan for a long in-line trench shielding system that met the soil and pipe requirements.
“We finalized a custom-designed system that combines a 34-foot and a 27-foot long trench box into one 61-foot modular unit,” said Samuels. “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.”
Trench Boxes Save the Day
Each trench shield is a custom-built Efficiency HT-8 model with sidewalls measuring 8 in. (20 cm) thick and 10 ft. (3 m) high, which include a specially engineered connecting-pin assembly that locks the boxes together on the ends of the adjoining sidewalls.
Pin-in-place spreader arches with 84-in. (213 cm) 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 boxes are equipped with 7-ft. (2 m) 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,” explained West. “In each situation, the contractor has been very happy with the trench shields, and they have worked very well.”
“These are the best darn ’shoes’ I’ve ever worked with,” said Schleis, “and I’ve been doing this for 30 years. I would certainly recommend this trench shielding system to other contractors.”
Schleis added that he is very happy with the progress his crew is making, installing approximately 450 ft. (137 m) of pipe per day (approximately nine pipe sections) through the open country.
The pipeline is being installed primarily in the right of way of rural county-owned roads, specifically County Trunk Q. The average trench depth is 14 ft. (4.3 m), progressing through ever-changing ground conditions.
“When completed, the new pipeline will have the capacity to deliver 23.5 million gallons of fresh potable water per day,” said Ron Umentum, president of the Central Brown County Water Authority. “It will certainly be capable of supplying this rapidly growing area with enough fresh drinking water for the foreseeable future.”
The new water supply will service approximately 237,000 residents in the communities of Bellevue, Ledgeview, Howard, Lawrence, Allouez, and De Pere.
The Right Tools for the Job
Undoubtedly, heavy machinery is necessary to manage the pipe installation and the two-shield combination, so PTS is using a Cat 385 excavator with a 5-yd. (4.5 m) bucket, in addition to a John Deere 992 backhoe for adding stone backfill. The job started Jan. 3 and is scheduled to be completed on time by Oct. 9.
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