Details:

Creators:
Yang, Lingqiang ; Zou, Qingping
Yang, Lingqiang ; Zou, Qingping Less -
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:

Supporting Files

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