2D FEM Modeling of Woodrow Wilson Bridge

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2-D FEM Modeling of Woodrow Wilson Bridge

• Joint ERC/SRC
• Hydraulic Engineers Meeting
• July 20, 2000
• Orlando, FL

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2-D Modeling of WWB
Alternate title Using internet data for 2-D
finite element modeling of estuarine waterways
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2-D Modeling of WWB

• Overview
• Modeling objectives
• Data sources
• Data processing
• 2-D modeling
• Uses made of model
• Conclusions (lessons learned)

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2-D Modeling of WWB

• Modeling objectives
• Become more familiar with SMS and Flo2DH
• Provide independent estimate of velocities
• Independent estimate of local scour at piers

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2-D Modeling of WWB

• Data sources
• Digital Raster Graphic of 124,000 USGS Quad used
  as base map
• NOAA/NOS 1 arc-second (30 m) Estuarine bathymetry
  used for elevations below MSL
• USGS 30 m Digital Elevation Model used for
  elevations above MSL
• Bridge data taken from preliminary design

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2-D Modeling of WWB
Digital Raster Graphic Image
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2-D Modeling of WWB
NOAA NOS Bathymetry Data (71 major estuaries)
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2-D Modeling of WWB
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2-D Modeling of WWB
http//www.mapfinder.nos.noaa.gov
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2-D Modeling of WWB
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2-D Modeling of WWB
http//edcwww.cr.usgs.gov
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2-D Modeling of WWB

• Data processing
• NOS bathymetry data
• Vertical datum MLLW
• elevation in meters
• DEM file format
• DEM data
• Vertical datum MSL
• elevation in feet
• SDTS file format
• Processing necessary to merge data sets

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2-D Modeling of WWB

• Convert DEM SDTS file to XYZ file
• change vertical scale to meters
• Convert NOS DEM file to XYZ file
• vertical datum shift from MLLW to MSL
• Import bathymetry data into SMS
• Import elevation data into SMS
• MESH gtgt SCATTERPOINT

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2-D Modeling of WWB

• Delete mesh
• Import geo-registered base map (DRG)
• Create FEM mesh using SMS tools

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2-D Modeling of WWB
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2-D Modeling of WWB
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2-D Modeling of WWB

• Hydraulic roughness adjusted until upstream WS
  elevation matched 1-D model with COE boundary
  conditions
• Model used to simulate
• Q100 existing
• Q100 proposed
• Q500 existing
• Q500 proposed

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2-D Modeling of WWB
Q100 WS elevation
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2-D Modeling of WWB
Q500 WS elevation
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2-D Modeling of WWB

• Provided independent estimates of approach
  velocities and depths for local scour analysis of
  proposed piers
• Both pier elements and large roughness used to
  simulate pier effects
• Model also used to evaluate effect of dredging on
  velocities and scour.

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2-D Modeling of WWB
Approach velocities Q100 (pier elements)
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2-D Modeling of WWB
Approach velocities Q100 (rough elements)
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2-D Modeling of WWB
Effect of dredging on velocities
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2-D Modeling of WWB
Effect of dredging on WS elevation
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2-D Modeling of WWB
2-D model used over300,000 elevation data points.
1-D model used 10 x-sections
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2-D Modeling of WWB
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2-D Modeling of WWB

• Conclusions
• For the scale of this problem the internet proved
  to be an excellent source of free, high quality
  data
• The 2-D model was versatile very useful for
  evaluating situations not originally anticipated
• The 2-D model was quicker to implement and more
  useful than HEC-RAS model

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2-D Modeling of WWB
Thank you! Questions?