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 Flood Damage Measuring Instruments Monitoring Real Time Information Scour Sensors State Of The Art Time Domain Reflectometers Turbulence

  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.
  
  
• Format:
  PDF
• Funding:
  SPR 692
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:2984b07b1d5fccf396821251c217a5f80a3ae2d4b9ecf50f2dbfd98f48af6e87
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31090/dot_31090_DS1.pdf
• File Type:
  [PDF - 3.73 MB ]