Genex Systems Scour Analysis and Sediment Transport
2G Robotics’ underwater laser scanners allowed Genex Systems to effectively and accurately model bridge scour and sediment transportation.
Genex Systems is a SDB Engineering, Scientific Research, and Information Technology services firm headquartered in Newport News, Virginia. Genex Systems was looking for a solution for modelling bridge scour and analyzing sediment transportation. The goal was to use a robotic arm to perform both dynamic and stationary scans with a 2G Robotics ULS-100 Laser Scanner. Tests were performed at the TFHRC J. Sterling Jones Hydraulics Research Laboratory in order to observe the capabilities of the scanner compared to incumbent technologies.
Sediment Transport Analysis
Sediment transport occurs in bodies of water as a result of current and tidal movement. Information obtained from sediment bed form analysis helps to determine areas where erosion or deposition will occur and aids with understanding bridge scouring. Genex Systems previously used a point laser distance sensor for bathymetry scanning work. The system was reliable and provided decent resolutions, but it did not work underwater.
To demonstrate the capabilities of the 2G Robotics ULS-100, the scanner was attached to a robotic arm which was mounted to an automated carriage that allowed the arm to move along the length of the trial channel. With this setup, power and communication were provided through the robotic arm and tests could be performed to gauge the measurement resolution capabilities of the ULS-100. This setup allowed the laser scanner to be operated in profile mode to dynamically scan the sediment bed load using a known constant linear velocity, specified by Genex Systems.
The tests were decisive and led to Genex Systems purchasing multiple units. Oscar Suaznabar, Research Hydraulic Engineer, stated that the ULS-100 produced “a stunning footprint laser line resolution of 0.83mm” at a scanning speed of 20mm/s.
Additionally, when scanning a small dolosse on the floor of the channel, the ULS-100 was able to capture the contour perimeter between the dolosse and the highly erodible channel bed. Understanding this contour is useful for monitoring the performance of scour countermeasures, such as dolosse or riprap, in the lab. Suaznabar noted that compared to a photo, “the laser scanning data made it notably easier to understand the contouring.”
Ultimately, Suaznabar explained that previously measuring the required space “was a matter of days. With the ULS-100, obtaining high resolution measurement data for a comparable area is a matter of minutes.”