Multi-Sensor Inspection: Advanced Condition Assessment of Sewer Force Mains Using MSI Technology

SewerVUE introduces the ability to scan, map, and localize large-diameter underground pipelines with an unprecedented combination of speed and precision. Pipeline stakeholders often require detailed analyses of their assets’ geometries and internal surface conditions. Precise pipeline analysis presents unique challenges: Global positioning systems will not work in underground pipes, and wheel-based odometry is unreliable, precluding external sensor localization. This paper explains how the multi-sensor condition assessment technique has overcome these obstacles using light detection and ranging devices, and other sensors mounted to a remotely driven vehicle through the pipeline, along with novel reconstruction algorithms. This paper presents a case study wherein this workflow was used for digitizing, localizing, and mapping 16,860 linear feet with a 48-in. pipe that makes up the South Shore Force Main in Milwaukee, Wisconsin. Here we inspected the interior of this asset with 3D LiDAR and video analysis. Advanced data processing methods allowed for unprecedented accuracy in reconstructing a digital double of this asset. Despite efforts to ventilate the pipe, visual conditions were limited during the inspection. This paper discusses the difference between a visual-only inspection and the insights learned from LiDAR intensity mapping in low visibility conditions.