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Publication Number: FHWA-HRT-09-028
Date: May 2009
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The Hydrodynamic Forces on Inundated Bridge Decks Study described in this report was conducted at the Federal Highway Administration's (FHWA) Turner-Fairbank Highway Research Center (TFHRC) J. Sterling Jones Hydraulics Laboratory and at the Department of Energy's Argonne National Laboratory's (Argonne) Transportation Research and Analysis Computing Center (TRACC). The study was in response to a request of several State transportation departments asking for new design guidance to predict hydrodynamic forces on bridge decks for riverine conditions. The study included experiments (physical modeling) at the TFHRC J. Sterling Jones Hydraulics Laboratory and High Performance Computational Fluid Dynamics (CFD) modeling at the Argonne National Laboratory. This report will be of interest to hydraulic engineers and bridge engineers who are involved in estimating loads for bridge decks. This report is being distributed as an electronic document through the TFHRC Web site (www.fhwa.dot.gov/research/tfhrc/).
Cheryl Allen Richter
Acting Director, Office of Infrastructure
Research and Development
Technical Report Documentation Page
|1. Report No.
|2. Government Accession No.||3 Recipient's Catalog No.|
|4. Title and Subtitle
Hydrodynamic Forces on Inundated Bridge Decks
5. Report Date
|6. Performing Organization Code|
Kornel Kerenyi, Tanju Sofu, and Junke Guo
8. Performing Organization Report No.
9. Performing Organization Name and Address
GKY and Associates, Inc.
4229 Lafayette Center Dr., Suite 1850
Chantilly, VA 20151
University of Nebraska
312 N. 14th Street
Alexander Building West
Lincoln, NE 68588-0430
10. Work Unit No. (TRAIS)
11. Contract or Grant No.
|12. Sponsoring Agency Name and Address
Office of Infrastructure Research and Development
Federal Highway Administration
6300 Georgetown Pike
McLean, VA 22101-2296
|13. Type of Report and Period Covered
November 2005-June 2008
14. Sponsoring Agency Code
FHWA Task Order 16
|15. Supplementary Notes
Contracting Officer's Technical Representative (COTR): Kornel Kerenyi, HRDI-07
The hydrodynamic forces experienced by an inundated bridge deck have great importance in the design of bridges. Specifically, the drag force, lift force, and the moment acting on the bridge deck under various levels of inundation and a range of flow conditions influence the design and construction of the bridge. This report explores the forces acting on bridges in two ways. First, through physical experimentation on scaled-down bridge deck models tested in a flume and then with computational fluid dynamics (CFD) simulation models. Three bridge deck prototypes were used for the experimentation: a typical six-girder highway bridge deck, a three-girder deck, and a streamlined deck designed to better withstand the hydraulic forces. The forces (expressed as nondimensional force coefficients) on each of the bridge deck shapes were measured in the laboratory with an ultra-precise force balance under a range of inundation scenarios (including partial inundation) and at four different velocities characterized by Froude numbers in the range of 0.16 to 0.32.
CFD modeling was performed using both the Fluent® and STAR-CD® software packages. The CFD models were calibrated to the flow conditions of the six-girder bridge, and these same conditions were used for the other two bridge shapes. A range of model options were tested including two-dimensional versus three-dimensional models, different mesh resolutions, boundary conditions, and turbulence models; their effect on the accuracy of results and processing efficiency were noted.
Fitting equations were generated to create an envelope around the experimental data and create design charts for each of the bridge types and force coefficients.
Finally, the CFD models, though they can match some of the general behavior of experimental models in terms of the relationship between inundation ratio and force measured at the bridge, do not yet faithfully reproduce the critical values of the hydraulic forces and show very little response to velocity. The CFD simulations seem promising as a method to test bridge designs, but more research is needed before complex designs can be tested wholly in the CFD realm. However, the design charts from the experimental results should be a valuable tool for the bridge designer in a wide range of design applications.
|17. Key Words
Hydrodynamic Forces, Force Balance, CFD, Inundated bridge decks
|18. Distribution Statement
No restrictions. This document is available to the public through the National Technical Information Service (NTIS), Springfield, VA 22161.
19. Security Classification
20. Security Classification
21. No. of Pages
|Form DOT F 1700.7||Reproduction of completed page authorized|
|ADV||Acoustic Doppler Velocimeter|
|Argonne||Department of Energy's Argonne National Laboratory|
|CFD||Computational fluid dynamics|
|FHWA||Federal Highway Administration|
|LES||Large Eddy Simulation|
|PIV||Particle Image Velocimetry|
|R&D||Research and Development|
|SIMPLE||Semi-Implicit Method for Pressure Linked Equations|
|TFHRC||Turner-Fairbank Highway Research Center|
|TRACC||Transportation Research and Analysis Computing Center|
|VoF||Volume of fluid|
|h*crit||Critical Inundation ratio resulting in maximum forces|
|hb||Height from bottom of flume to bottom of bridge|
|hu||Height of water from bottom of flume|
|Mcg||Moment about the center of gravity|
|V, v||Free stream velocity|
|ρ||Fluid density (or water density)|
Topics: research, infrastructure, structures, bridge hydraulics, scour
Keywords: Bridge decks, bridge design, bridge foundations, bridge hydraulics, bridge inundation, bridge scour, pressure flows, pressure scour, submerged flows