A Modern Solution for an Old Problem—Utilizing both CIPP and CFRP for Aerial Pipeline Rehabilitation

What happens when you determine one rehabilitation technology isn’t sufficient enough? The internal or external rehabilitation of aerial piping can be a tricky concept when utilized as an either/or repair option, but when combined, these technologies can prove to complement one another and provide a fully structural repair solution not previously considered in our industry. For a municipality in North Texas, they are no stranger to this design challenge, but they had never considered the combination of these technologies until it was presented as one design solution procured under one contract. By consulting with their partners, they realized that this problem could be overcome by implementing both an internal and external repair solution. This paper will focus on two aerial pipes, 12-inch and 18-inch steel pipes, which were showing signs of severe deterioration. The design team determined that the pipes would be internally rehabilitated with cured-in-place pipe (CIPP) to eliminate internal corrosion; then, to provide additional protection due to environmental exposure and provide additional longitudinal strength, the use of carbon fiber reinforced polymer (CFRP) systems was designed to be applied to the exterior. This paper will discuss the city’s struggle with this issue and the process that led to this unique repair option. The design procedures and the construction details will also be discussed and illustrated.