Monitoring the effects of knickpoint erosion on bridge pier and abutment structural damage due to scour.

Details

• Creators:
  Papanicolaou, A.N. Thanos ; Admiraal, David ; Wilson, Christopher ; Kephart, Clark
• Corporate Creators:
  Mid America Transportation Center
• Subject/TRT Terms:
  • Degradation (Hydrology)
  • Channels (Waterways)
  • Scour
  • Geotechnical engineering
  • Flow measurement
  • Bridge abutments
  • Bridge piers
  • Structural analysis
• Publication/ Report Number:
  25-1121-0001-471 ; 25-1121-0001-424
• Resource Type:
  Tech Report
• Geographical Coverage:
  Iowa
• Corporate Publisher:
  United States. Dept. of Transportation. Research and Innovative Technology Administration
• NTL Classification:
  NTL-HIGHWAY/ROAD TRANSPORTATION-Bridges and Structures
• Abstract:
  The goal of this study was to conduct a field-oriented evaluation, coupled with advanced laboratory techniques, of channel ; degradation in a stream of the Deep Loess Region of western Iowa, namely Mud Creek. The Midwestern United States is ; an ideal place for such a study considering that ~$1 Billion of infrastructure and farmland has been lost recently to channel ; degradation. A common form of channel degradation in this region is associated with the formation of knickpoints, which ; naturally manifest as short waterfalls within the channel that migrate upstream. As flow plunges over a knickpoint face, ; scouring of the downstream bed creates a plunge pool. This downcutting increases bank height, facilitating bank failure, ; stream widening, and damage to critical bridge infrastructure. We conducted a state-of-the-art geotechnical analysis of the ; sediments from the knickpoint face, plunge pool, and adjacent stream banks to determine the areas of the streambed near ; the bridge infrastructure that favor knickpoint propagation. Soil characterization using particle size distributions and ; Gamma Spectroscopy identified a stratigraphic discontinuity at the elevation where the knickpoint forms. An automated ; surveillance camera was established to monitor the location of the knickpoint face relative to a fixed datum and provide a ; first-order approximation of its migration rate, which was approximately 0.9 m over a 248-day study period. Surveys ; conducted of the stream reach also facilitated information about knickpoint migration. Flow measurements using Largescale ; Particle Image Velocimetry were conducted during the study to understand the hydrodynamic conditions at the site. ; The results of this research will assist local and federal transportation agencies in better understanding the following: (1) ; principal geotechnical and hydrodynamic factors that control knickpoint propagation, (2) identify necessary data for ; extraction and analysis to predict knickpoint formation, (3) provide mitigation measures such as grade control structures ; (e.g., sheet-pile weirs, bank stabilization measures) near bridge crossings to control the propagation of knickpoints and ; prevent further damage to downstream infrastructure.
  More +
• Format:
  PDF
• Funding:
  MATC TRB RiP No. 28504
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/23120/dot_23120_DS1.pdf
• File Type:
  [PDF - 3.21 MB]
• Collection(s):
  University Transportation Centers ; US Transportation Collection
• Main Document Checksum:
  urn:sha-512:5c8572f4afe42ff3cbbd991b09ab0963dd53e2cf9bb559ea0f503c0b7396213e4d8d59123b61881c04dfe974269974c1e9f9d24446e8035662e4a7d194a1e127