Wastewater operators have long been aware that environmental and structural factors impact a sewer pipe’s service life. But they often rely on gut and experience to guide their decisions regarding which lines are most at risk.
Experts from the Civil Environmental and Geodetic Engineering department at The Ohio State University have put a scientific spin on this process. In a recent study, researchers conducted statistical analyses to investigate the most common factors in concrete sewer line failure and collapse.
They know that the stakes for the nation’s utilities are high. “In 2017, the American Society of Civil Engineers gave the United States’ overall sewer system a D+ rating,” explained Soroush Zamanian, one of the report’s authors, to Ohio State News. “And that’s part of why we are looking at this question and seeing if we could help predict where lines might fail.”
To run the study, the researchers gathered and analyzed data from underground concrete pipes in the United States. They investigated 16 common causes of sewer pipe failure, including the density and makeup of surrounding soil, the elasticity and strength of the concrete materials and the weight of ground-level vehicular traffic that passed over different lines. After running various statistical analyses, they determined that two of these factors were most likely to lead to pipe cracking and failure: weak concrete (either made of poor materials or poorly maintained) and the weight of trucks that drove over them on a regular basis.
This study has provided clear, data-driven insight into the importance of varying factors in a sewer pipe’s service life. “The big picture is if we want to design sewer pipes for the future, or if we want to assess the current condition and predict future conditions of these pipes, one key element is to know the important factors contributing to their failures – and how do those factors play out in the real world,” Zamanian said. Many operators maintain hundreds or thousands of miles of pipe, and knowing which lines are likely to fail sooner can help them prioritize and schedule regular inspections to ensure structural integrity is maintained, and to catch existing problems before they become crises. In addition, these findings can help installers improve outcomes for future pipes by selecting stronger, longer-lasting materials or placing pipes in locations that don’t experience heavy truck traffic.
Every bit of information can help when it comes to maintaining a sewer system, whether it’s risk factors for pipe failure or additional inspection data. Envirosight’s Phased Assessment Strategy for Sewers (PASS) enables wastewater operators to work more efficiently by gaining a system-wide understanding of infrastructure condition and prioritizing resource allocation. Read our white paper on the topic and discover how your crew can work smarter, not harder.