# Presentation: 262515

## 2-D FEM Modeling of Woodrow Wilson Bridge

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

## 2-D Modeling of WWB

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

## 2-D Modeling of WWB

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

## 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

## 2-D Modeling of WWB

- Data sources
- Digital Raster Graphic of 1:24,000 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

## 2-D Modeling of WWB

- Digital Raster Graphic Image

## 2-D Modeling of WWB

- NOAA NOS Bathymetry Data
- (71 major estuaries)

## 2-D Modeling of WWB

## 2-D Modeling of WWB

- http://www.mapfinder.nos.noaa.gov

## 2-D Modeling of WWB

## 2-D Modeling of WWB

- http://edcwww.cr.usgs.gov

## 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

- 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

- 2-D Modeling of WWB

## 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 >> SCATTERPOINT

## 2-D Modeling of WWB

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

## 2-D Modeling of WWB

## 2-D Modeling of WWB

## 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

## 2-D Modeling of WWB

- Q100 WS elevation

## 2-D Modeling of WWB

- Q500 WS elevation

## 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.

## 2-D Modeling of WWB

- Approach velocities Q100 (pier elements)

## 2-D Modeling of WWB

- Approach velocities Q100 (rough elements)

## 2-D Modeling of WWB

- Effect of dredging on velocities

## 2-D Modeling of WWB

- Effect of dredging on WS elevation

## 2-D Modeling of WWB

- 1-D model used
- 10 x-sections

- 2-D model used over300,000
- elevation data points.

## 2-D Modeling of WWB

## 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

## 2-D Modeling of WWB

- Thank you!
- Questions?