Pipe Penetrating Radar: Performing Advanced Condition Assessment on Gravity Sewers

Pipe penetrating radar is a condition assessment technology that uses high-frequency ground-penetrating radar from inside non-ferrous pipes. It sees past the pipe’s inner surface, measures the pipe wall’s thickness, and detects voids. With millimeter accuracy, pipe-penetrating radar can detect voids while still small and well before they develop into sinkholes. This paper will look at how pipe penetrating radar is used as part of effective asset management plans through a case study on a recent project. Milwaukee Metropolitan Sewerage District chose SewerVUE Technology Corp. to determine the concrete thickness and map reinforcing rebar for some linear assets. A complex manned-entry pipe-penetrating radar survey was undertaken to assess the conditions of two sections of a reinforced concrete force main with different diameters running through the Jones Island Peninsula in Milwaukee, Wisconsin. More than 1,110 ft of line data was collected. The survey detected no significant variance in the inside and the outside surfaces of the pipe walls; however, a few sections were found to be delaminating. We completed the inspections in a single day and delivered the pipe penetrating radar data, reporting anomalies, wall thickness, and reinforcement positioning. Pipe penetrating radar is a valuable tool for effective asset management plans. By measuring wall thickness and detecting voids early, owners and managers can prioritize rehabilitation for pipes where it is needed most.