Real time measurement of scour depth around bridge piers and abutments : final report.

Details

• Creators:
  Khan, Abdul A. ; Atamturktur, Huriye S.
• Corporate Creators:
  Clemson University. Glenn Department of Civil Engineering
• Corporate Contributors:
  South Carolina. Dept. of Transportation. Office of Materials and Research ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Accuracy
  • Bridge abutments
  • Bridge piers
  • Field tests
  • Measuring instruments
  • Monitoring
  • Real time information
  • Scour
  • Sensors
  • State of the art
  More +
• Publication/ Report Number:
  FHWA-SC-14-05
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Edition:
  Final report, January 2011 to January 2015
• Corporate Publisher:
  Clemson University
• Abstract:
  Scour is one of the most significant threats to bridge infrastructure and is the leading cause of failure within the ; United States. Scour monitoring is an approved countermeasure as reported by the Federal Highway Administration. As ; the monitoring techniques available range from simple devices that rest on or in the channel bed to advanced scanning ; systems that provide a bed contour profile, a concise study of the state of the art in real time scour measurement ; capabilities is required. ; The available techniques for monitoring scour are reviewed to highlight the governing physics, to evaluate field ; performance, and to identify the effect of environmental factors on accuracy and reliability. From this assessment, two ; devices are selected for further study: a sonar fathometer and a Time Domain Reflectometry (TDR) device. A novel ; device, called a Vibration-based Turbulent Pressure (VTP) sensor, is proposed which exploits the turbulence in open ; channels to locate the bed level. This sensor vibrates at significantly higher amplitude when in the channel flow relative ; to an identical sensor located in the sediment. ; The vibration-based method, time domain reflectometry, and sonar devices are evaluated against simulated field ; conditions in order to determine their relative sensitivities to environmental conditions. These tests reveal that sonar and ; time domain reflectometry devices can be influenced by channel salinity and temperature. In addition, the sonar device is ; shown to be sensitive to the suspended sediment concentration in the channel, its height relative to the bed, and bed ; topography within the sonar beam. The vibration-based method is shown to be the least sensitive to environmental ; factors in the channel. In addition, the VTP device can provide reliable results in highly misaligned flows. Finally, the ; performance of TDR, sonar, and the vibration-based technique is evaluated under field conditions. ; The field tests reveal that all instruments perform at their accuracy level. The sonar must be deployed close to the ; bed to guarantee that the beam will be contained within the scour hole and would not have large width. In addition, the ; site should not have high suspended load concentration. The TDR is insensitive to suspended sediment; however, salinity ; greater than 0.5 parts per thousand renders the instrument inoperable. The VTP is proven to be insensitive to all the ; environmental factors. However, field deployment reveals that debris accumulation may cause the instrument to report ; false bed location.
  More +
• Format:
  PDF
• Funding:
  SPR 692
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31090/dot_31090_DS1.pdf
• File Type:
  [PDF - 3.73 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:2984b07b1d5fccf396821251c217a5f80a3ae2d4b9ecf50f2dbfd98f48af6e87