Pre-chlorinated Pipe Bursting in Altamonte Springs, Florida

In 2015, the City of Altamonte Springs began a shift to a trenchless approach of water main replacement with pre-chlorinated pipe bursting.

Altamonte Springs is at the heart of central Florida located within the suburbs of the Orlando-Kissimmee-Sanford Metropolitan area. Just eight miles north of Orlando, one of Central Florida’s busiest municipalities, and 30 miles north of Disney World, Altamonte Springs is home to a growing number of young professionals. This vibrant and emergent community maintains a small-town vibe with city amenities that appeal to residents of all ages.

Altamonte Springs was established in 1920 and maintains an extensive network of water distribution pipelines serving over 55,000 residents. With aging water infrastructure and continued economic growth, the need to replace, rehabilitate and improve the current system has become a daunting but necessary task.

This new approach minimized disruption to established neighborhoods and allowed for a broader scope of water infrastructure replacement in a lesser time frame. Over the past seven years, the City of Altamonte Springs has partnered with Murphy Pipeline Contractors (MPC) to replace approximately 15 miles of water main employing the pipe bursting technology.

The use of pipe bursting as a viable option to traditional open-cut has been quickly gaining momentum in urban areas, including both residential and business districts. This is due to the fact that pipe bursting allows for a much smaller impact on communities, cutting down on the need for extensive restoration (i.e., replacing roads, sidewalk, driveways, etc.). This not only decreases the overall project schedule, minimizing construction footprint within neighborhoods, but is sometimes half the cost of traditional open-cut. With the replacement of a water main via pipe bursting, the disruption to a community’s water service is minimal, often only hours while the new system is being activated. Water systems can be replaced, activated, and neighborhoods restored in record time.

The pre-chlorinated pipe bursting method utilizes high-density polyethylene (HDPE) pipe and entails the pre-assembly and testing of approximately 500-to-600-ft lengths of pipe above grade at a nearby staging location. All AWWA standards are followed. This work is completed in advance of pipe bursting operations. Once the pipe string is proven to be sound by the testing and disinfection procedures, bursting operations can begin. To minimize disruption of water service to residents, a temporary bypass system is utilized to ensure residents maintain continuous service as the water main is being replaced. In the area of the water main being replaced, a series of small pits are excavated, and the new pipe is pulled into place by pipe bursting through the existing main. A post-chlorination and flushing of the main is then performed and the new line is connected to the distribution system. All services are connected to the new main and the surface area is backfilled to preconstruction grade; the entire process is completed within a single day within six to eight hours.

One of the City of Altamonte Springs first projects utilizing the trenchless technology of pipe bursting, began in 2015 with Murphy Pipelines. Considerable research went into pre-chlorinated pipe bursting as a means of water main replacement. In addition, the research included a better understanding HDPE pipe as the water operations and maintenance team had concerns with their lack of familiarity with the pipe material. They did not want to own fusion equipment, stock additional fittings and send their crews for regular training. Historically they were familiar with bell and spigot PVC, which had been installed with open cut. However once the team understood they could work with HDPE pipe using mechanical connection methods in the same way as PVC pipe, their concerns quickly abated.

With the success of the pilot project, the City added an increasing number of pipe bursting projects to their portfolio, averaging one water main replacement project per year for the past seven years. In July of this year, MPC replaced close to 4,300 lf of 6-in. water main and connected 65 services in less than four weeks. The restoration was minimal, with only 27 sq yds of asphalt, and 17 sq yds of sidewalk replacement needed project wide. The project finished 20 percent under budget and ahead of schedule.

MPC construction manager, Lauren Romero, stated this when asked about the benefits of pipe bursting in this community, “We were able to complete all of the pipe installation, restore the area, and get our equipment out in the same amount of time it would have taken an open cut contractor to destroy one block. The results speak for themselves.”

The ability to perform utility upgrades at such a significantly lower cost allows for an aggressive approach in moving forward with additional improvements. The savings to taxpayers alone is enough to make this approach relevant but coupled with the fact that the disruption and inconvenience to residents and businesses are minimal compared to traditional methods of utility replacement, make this approach a new favorite among municipalities.

Pre-chlorinated pipe bursting has quickly become not only a viable option but a desired one in many cities throughout the United States. In a world that is faced with aging infrastructure and a growing population, as well as inflated construction costs, trenchless technology opens the door for a brighter future.

Cynthia Viers is a project manager with Murphy Pipelines. Richard Crow is the director of engineering and special projects with Murphy Pipelines.