The City of Billings, particularly its West End, is one the state’s fastest growing communities in Montana. Keeping future expansions and its current infrastructure in mind, the city determined that it was time to upgrade its 1980s-era wastewater system.
Based on their 2018 study, Morrison-Maierle designed a 4,735 linear-foot trenchless rehabilitation solution for this busy area’s 60-inch sanitary sewer interceptor main. Instead of tearing up streets, railroads, and pedestrian walkways
to replace the whole pipe, they used the cured-in-place pipe (CIPP) method to avoid open cut excavation as the project went through downtown, the railroad right-of-way, Highway 87, and a state superfund site. The project team also lined 13 manholes with a polyurea liner to avoid the costly replacement of large tee and box manhole structures.
The CIPP liner solution also addressed the pipe’s structural deficiencies, improved the interceptor’s hydraulic performance, kept impacts to the public at a minimum, and extended the life of the existing pipe by 50-to-100 years. This will be a significant cost savings for the city over time.
The project team evaluated Sonar and other 3D technologies, however it was not cost advantageous to the city. Manual surveys were conducted at manholes to estimate sediment layering and build up in the pipe. A drone survey was used to confirm final sediment volumes.
To execute this project, Morrison- Maierle started by designing a bypass pumping solution with a siphon box that was operated around the clock during construction. Large in scale and taking more than four weeks to set up, the pumping system ran nearly a mile in length. Morrison-Maierle utilized infrastructure such as a livestock underpass and a bike path under the Highway 87 bridge to route the pipe in order to avoid creating more obstacles than necessary for the public.
As a result of careful study, planning, and design, this project was constructed in 40 days with zero disruptions in service, and minimal impacts to the public.