Manning's roughness coefficient for buried composite arch bridges.

Details

• Creators:
  Yang, Lingqiang ; Zou, Qingping
• Corporate Creators:
  University of Maine. Advanced Structures and Composites Center
• Subject/TRT Terms:
  Arch Bridges Concrete Fiber Reinforced Polymers Flow Measurement Hydraulics Roughness Coefficient Streamflow Tubing
• Publication/ Report Number:
  ME 14-15
• Resource Type:
  Tech Report
• Geographical Coverage:
  Maine
• Corporate Publisher:
  Maine. Dept. of Transportation
• Abstract:
  This report includes fulfillment of Task 9 of a multi-task contract to further enhance concrete filled FRP tubes, or
  
  the Bridge in a Backpack. Task 9 investigates the interaction of water flow under the bridge with the tubes and
  
  decking and recommends Manning’s roughness coefficients for water flow under the composite backpack bridge
  
  system.
  
  There are three flow regimes and each has a different resistance relationship. Quasi-smooth flow occurs only when
  
  there are depressions or when roughness elements are spaced very close. Hyper-turbulent flow occurs when
  
  roughness elements are sufficiently close so each element is in the wake of the previous element and rough surface
  
  vortices are the primary source of the overall friction drag. Isolated roughness flow occurs when roughness spacing
  
  is large and overall resistance is due to drag on the decking surface and form drag on the arches. Due to the large
  
  sizes of the tubes and tube spacing, the conventional method of computing roughness coefficient using the formula
  
  for rough pipe is not applicable here. Instead, we have to use a more complex procedure to calculate the roughness
  
  coefficient using different formula for different flow regimes described above.
  
  In this report, Manning’s roughness coefficients are provided when the flow is perpendicular to the bridge and when
  
  the angle between flow and the bridge is 45 and 30 degrees (Appendix 1). Depending on the arch radius and tube
  
  size and spacing, Manning’s roughness coefficient of the bridge ranges from 0.016 to 0.045, which is significantly
  
  larger than that for smooth concrete (n=0.012), due to the large tubes underneath the bridge. These results are
  
  important findings and should be incorporated in a hydraulic model such as HECRAS to more accurately predict
  
  water flows and backwater profiles at the FRP tubular bridge.
  
  
• Format:
  PDF
• Funding:
  20111223*2878
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:965725a210264ef0cf5233c14186dc75c364d3341e345dbb9510648af8bbd4fc
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/28488/dot_28488_DS1.pdf
• File Type:
  [PDF - 3.44 MB ]