Abstract
Thousands of bridges throughout the United States have been identified as being scour critical (i.e., susceptible to failure from pier and (or) abutment scour). Scour occurs during times of rapid river flow when sediments, including rocks, gravel, and silt, are transported by the currents, undermining bridge pier foundations and similar structures. It can be increased by the presence of an ice cover. The scour process is dynamic; erosion and deposition can occur during the same high-energy river event, so the worst-case and the net effect cannot be easily predicted or dynamically monitored using previously available equipment. Herein, a technique and system (U.S. Patent #5,790,471) employing frequency modulated - continuous wave (FM-CW) reflectometry are discussed. This system is proposed for continuous monitoring of the extent of scour around riverine structures. A bench scale version of the system with a 490-MHz linearly swept bandwidth was implemented and tested in the laboratory, where sediments were incrementally added to a water-filled plastic barrel containing an 86-cm-long scour probe. Reflectometer data were taken after each increment of sediment was added. The data indicating the sediment boundary were plotted in a waterfall format that clearly shows the progressive sedimentation. This system has the potential for continuous round-the-clock operation and accuracy to within 5 cm of sediment depth. Key words: reflectometry, real-time monitoring, frequency modulated continuous wave, scour, sediment transport.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.