New Technologies and Applications of a Multi-Sensor Condition Assessment for Large-Diameter Underground Pipe Infrastructure

This paper describes the development and successful applications of a robust closed-circuit television (CCTV), LiDAR and sonar based pipe inspection system to gather quantitative data for critical underground pipe condition assessment. The system that can be deployed on a remotely operated vehicle (ROV) or on a float produces accurate cross-sectional analysis and sediment volume. This capacity is increasingly critical in large diameter pipes with high level of flow. The system employs a time of flight LiDAR with sub centimetre distance resolution. Results from recent projects are discussed, in detail in this paper. The Townline Road and Gladys Avenue Trunk sewers in Abbotsford, British Columbia, Canada are critical lines in the municipality’s waste-water system. These reinforced concrete interceptors range between 525 mm (20 inches) and 1050 mm (41.3 inches) diameters with highly variable flow conditions. Hard to access, off-street manholes created challenges during deployment. The robust, yet modular SewerVUE multi-sensor pipe inspection system (MPIS) was repeatedly reconfigured during the project to accommodate the challenging site conditions. The sonar results provided accurate sediment volumes and cross sectional restrictions. LiDAR data and a proprietary 4 in 1 visualization module complemented the deliverables. The avenue Lenine combined sewer in Saint Denis, a northern suburb of Paris, France is a critical interceptor in the city’s collection system. This 1400 mm (55.1 inches) diameter reinforced concrete pipe experiences wet weather overflows during extreme rainfall events. The primary objective of the survey was to quantitatively measure sediment volume and distribution within a 2134 m (7646 ft) long section. This paper presents the methodology and the results of the inspection. Advanced pipe condition assessment technologies, such as the CCTV, LIDAR and sonar system described in this paper are cost-effective, and quantitative methods that provide critical information for optimal operation and maintenance of pipe infrastructure. The reported results can also help better refine estimated remaining service life of an interceptor, accurately determine the overall severity of pipe degradation, as well as provide a basis for improved cost allocation and timing of rehabilitation efforts.