fhwa’s future scour design approach · in situ scour testing device (istd) proposed future scour...
TRANSCRIPT
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
FHWA’s Future Scour Design Approach
presented at the
Bridge Scour Technology Transfer Workshop
in
Dimondale, Michigan
by
Kornel Kerenyi
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
2017Physical Modeling 40 %
Numerical Modeling 60 %
Hydraulics Lab Overview
Live Bed Bridge Scour Experiments
Robotic Arm Carriage System
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Erosion Force
y
Concept of Hydraulic loading and Erosion force Decay Function2018
Physical Modeling 35 %
Numerical Modeling 65 %
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Erosion Force
y
Concept of Hydraulic loading and Erosion force Decay Function2018
Physical Modeling 35 %
Numerical Modeling 65 %
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Erosion Force
Concept of Hydraulic loading and Erosion force Decay Function2018
Physical Modeling 35 %
Numerical Modeling 65 %
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Erosion Force
y
Concept of Hydraulic loading and Erosion force Decay Function2018
Physical Modeling 35 %
Numerical Modeling 65 %
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
yEstimated ysLevel 1
Uncertainty
Factored Resistance
Nominal Resistance
True ys
ASSUMED UNIFORM SOIL
2018Physical Modeling 35 %
Numerical Modeling 65 %
Concept of Soil Erosion Resistance Level 1: Using current assumptions of uniform soil (e.g. D50)
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
y
Estimated ysLevel 2
Uncertainty
Factored Resistance
Nominal Resistance
True ys
Boring Logs from Historical
Records
2018Physical Modeling 35 %
Numerical Modeling 65 %
Concept of Soil Erosion Resistance Level 2: Soil Erosion Resistance Data from Historical Records
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
y
Estimated ys
Level 3Uncertainty
Factored Resistance
Nominal Resistance
True ys
Soil Erosion Resistance = f (PI,
Cu, …)
2018Physical Modeling 35 %
Numerical Modeling 65 %
Concept of Soil Erosion Resistance Level 3: Soil Erosion Resistance from Geotechnical Properties
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
y
Estimated ys
Level 4Uncertainty
Factored Resistance
Nominal Resistance
True ys
Shelby Tube Sample for Lab Erosion
Testing
2018Physical Modeling 35 %
Numerical Modeling 65 %
Concept of Soil Erosion Resistance Level 4: Soil Erosion Resistance from Lab Erosion Testing
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
y
Estimated ys
Level 5Uncertainty
Factored Resistance
Nominal Resistance
True ys
2018Physical Modeling 35 %
Numerical Modeling 65 %
Concept of Soil Erosion Resistance Level 5: Soil Erosion Resistance from In-situ Scour Testing
Devices
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
2020Physical Modeling 30 %
Numerical Modeling 70 %
Hydraulics Lab Overview
Automation of Soil Erosion Resistance Experiments
Programmed Robotic Arms performing experiments
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
2030Physical Modeling 20 %
Numerical Modeling 80 %
Potential Future Procedure for Determining Soil Erosion
Resistance
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Hydraulic Loads
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Example: Feather River Bridge, Sacramento, CA, Scour Study
MFS and CFD to Determine Shear Erosion Forces
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
MFS and CFD to Determine Shear Erosion Forces (cont’d)
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
5 ft
ys
5 ft
Digitized Scour Bathymetry
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
8 ft
ys
8 ft
Digitized Scour Bathymetry (cont’d)
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
9.5 ft
ys
9.5 ft
Digitized Scour Bathymetry (cont’d)
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
11 ft
ys
11 ft
Digitized Scour Bathymetry (cont’d)
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
CFD for Computing Decay of Shear Erosion Forces
Shear Stress21 Pa
21 Pa
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Shear Stress
13 Pa
ys
5 ft
CFD for Computing Decay of Shear Erosion Forces (cont’d)
13 Pa
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Shear Stressys
8 ft10 Pa
CFD for Computing Decay of Shear Erosion Forces (cont’d)
10 Pa
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Shear Stressys
9.5 ft7 Pa
CFD for Computing Decay of Shear Erosion Forces (cont’d)
7 Pa
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
6 Pa
Shear Stressys
6 Pa11 ft
CFD for Computing Decay of Shear Erosion Forces (cont’d)
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Soil Erosion Resistance – Testing
• In-situ Scour Testing Device
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Proposed Future Scour Depth Design Method
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Proposed Future Scour Depth Design Method (cont’d)
0 Soil Resistance
y
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
In Situ Scour Testing Device (ISTD)
Proposed Future Scour Depth Design Method (cont’d)
0 Soil Resistance
y
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Proposed Future Scour Depth Design Method (cont’d)
0 Soil Resistance
y
In-situ Scour Testing Device Research
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
In-situ Scour Testing Device Concept (cont’d)
A-AA
B
B-B
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
In-situ Scour Testing Device Concept (cont’d)
A-AA
B
B-B
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
In-situ Scour Testing Device Concept (cont’d)
A-AA
B-B
B
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Soil Erosion Resistance - Testing
• Ex-situ Scour Testing Device
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Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
0
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0 1 2 3 4 5 6 7
Ero
sio
n R
ate
mm
/hr
Shear Stress t (Pa)
Erosion Rate Curve
Test Data
Curve Fit
tc
Erosion Rate Curve is used for determining the
Critical Soil Erosion Resistance (tc)
Hydraulic EngineeringU.S. Department of Transportation
Federal Highway Administration Hydrology Drainage Culverts Bridges CoastalScour
Thank You