Four months may sound like a generous amount of time to replace 2,200 feet of water pipe in an urban setting, but doing so in the middle of a Colorado winter – while coordinating two crews working a mile apart – is quite a feat.
The need for this formidable task became apparent when Denver Water, which serves high-quality water to 1.5 million people in the city of Denver and surrounding suburbs, made an important discovery.
“We take a proactive approach to inspecting our pipes to locate problems and prioritize when and where to replace sections of pipeline before they fail,” said Garrick Thompson, engineering design project manager at Denver Water. “After a review of data collected from electromagnetic and acoustic fiber optic systems, we identified several problem areas along Conduit 94 [in north Denver].”
As a result, the utility decided to fully replace 2,200 feet of the pipeline in two places: under Tennyson Street, which is next to Willis Case Golf Course, and along West 50th Avenue, in front of Regis University. During the summer irrigation season, when water use is the highest, around 30 to 40 million gallons of water can flow through the pipeline every day.
The pipeline was built in 1977 using pre-stressed concrete cylinder pipe. These pipes consist of a concrete core, a thin steel cylinder with a wire wrapped around it, and a mortar coating on the outside.
“Unfortunately, in the years since the pipe was installed,” Thompson continued, “pipes made by one manufacturer in the mid-1970s are now known to experience breaks in the wires, which reduces the structural integrity of the pipe. This defect puts the pipe at higher risk of failure.”
Enter Henderson, Colorado-based BT Construction Inc. (BTC), which won the pipe replacement contract from Denver Water and selected 66-inch AMERICAN SpiralWeld Pipe as the replacement product.
“Denver Water has been one of our key clients since we were founded in 1980,” said BTC Project Manager Kevin Juliano. “This was the first time we’ve worked with AMERICAN on a Denver Water steel pipe project, and we knew about AMERICAN’s solid reputation in the industry.”
Jeff Blakely, who was the AMERICAN sales engineer for the project, said, “We have supplied Denver Water with AMERICAN Ductile Iron Pipe for years, but this was only the second time we have provided our steel pipe products.” AMERICAN partnered with another contractor in 2018 to replace pipe on Denver Water’s Conduit 16 West.
The Conduit 94 project was completed on time in early 2021 despite a number of challenges. Thompson says the COVID-19 pandemic was only one of them. “Traffic control was also a major challenge throughout the project, as the pipe replacement occurred under a street right next to a major university [Regis University], a neighborhood and a golf course. The team worked with the university and the city of Denver to develop a safe and effective solution to keep traffic clear of the site and to replace the pipeline sections without interruption to schedule.”
Juliano said, “We opted to use two crews simultaneously to meet the deadlines. Each of the two replacement locations were about 1,000 feet long and about a mile from each other. We couldn’t work at night because of being in a residential area, but we had some long days through the winter, including a few weekends. Snowy weather only shut us down a total of three days, so we were often working when other construction crews would not.”
AMERICAN’s intense focus on planning and on-time delivery played a part in the project’s success. “Despite COVID-19 related impacts to the project, AMERICAN was able to provide us with their products on schedule and according to project specifications,” Thompson said.
“AMERICAN had exceptional communication with us from the very beginning of the Conduit 94 project,” Juliano said. “There was no room to stage any of the pipe, so delivery coordination was crucial. They were very good about meeting delivery expectations.
“AMERICAN’s pre-construction plan and the way they approached the submittals and drawings before construction started was very well organized,” Juliano continued. “They had all the right people at the table at the same time and gathered all the necessary information they needed before they started making pipe. I was very impressed with their pre-construction systems.”
Blakely agrees that AMERICAN’s partnership with BTC was a success. “BTC is fantastic to work with. Our companies align well, and, like AMERICAN, they treat people the right way. Also like us, they love to work on challenging projects.”