1
In Situ Erosion Evaluation Probe
(ISEEP)
PI: Mo. Gabr
North Carolina State University (NCSU)
Ph.D. Student: Mohamad Kayser (Graduation 2014)
MS Students: Yulian Kebede, Chris Stryffeler, Steven Toebben (Graduation 2014)
Cary Caruso and Austin Key (Graduated)
Summer Interns: Yulian Kebede - Jackson State University
Ian McMillan- The Citadel
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
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Project Overview
Scope: Enhancing Capabilities for Rapid Assessment
of Erosion/Scour Potential
In Situ Erosion Evaluation
Approach: An in situ process to assess critical
erosion/scour parameters:
oThreshold Stream Power
oErosion Rate per unit stream power
Probe (ISEEP)
Motivation: What is available?


Methods to measure scour potential with
depth require sample removal and lab
testing
or
only
provide
surface
measurements
Methods for rapid assessment of scourability
are lacking in literature
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
3
DHS Mission Relevance
DHS Mission 5, Ensuring Resilience to Disaster: a tool to assist in fulfilling the
DHS mission of infrastructure protection and hazard mitigation

Rapid deployment over a large area to assess incipient erosion of soil profiles
supporting protective structures with approaching storm events

Rapid post storm assessment for locating temporary support infrastructures - an
important aspects of emergency management

State and Federal government agencies and private consultants can utilize the
device data for: i. hazard mitigation, ii. enhanced preparedness, iii. effective
emergency response, and iv. rapid recovery:
 Frequent measurement of scour potential (i, ii)
 Identify scour-critical structures for retrofit and action plan (i, iii)
 Provide data to estimate post storm stability and time-dependent stability of critical
structures (iii, iv)
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
Introduction
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Motivation
Enhancing Capabilities for Rapid Assessment of Erosion
Potential of Critical Structures
Bridges
The Guardian, 2009
Dams and Levees
Roads and
Coastal Structures
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
Existing Approaches
5
ISEEP’ Approach
Ettema, R., Constantinescu, G. and Melville, B. (2011.)
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
Existing Approaches
Research Lead  The University of North Carolina at Chapel Hill
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CHC-R 5th Annual Meeting
January 31-February 1, 2013
Existing Approaches
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Richardson and Davis (2001)
 y
 2.0 K 1 K 2 K 3 K 4 K w  
a
a

K = pier nose shape (0.9 and 1.1)
ys
0 . 35
0 . 43
Fr
1
K2 = angle of attack of flow (1.0 and 5.0)
K3 = state of bed-sediment motion (1.1 and 1.3)
Kw = correction factor
K 4  0.4 V R
0.15
VR 
V  V icd 50
V cd 50 V icd 90
Vicdx is approach velocity required to initiate scour at the pier for grain size
Dx, given by:
V icdx
 Dx 
 0.645 

 a 
0 . 053
V cdx
V cdx  6.19
 y 1 / 6 D 1/3
x
Research Lead  The University of North Carolina at Chapel Hill
Fr 
V
gy
CHC-R 5th Annual Meeting
January 31-February 1, 2013
Existing Approaches
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A Better Approach?
Erosion Parameters
 Assess
•
•
Erosion Parameters of Soil:
Critical Shear Stress
Detachment Coefficient
 Assess
Shear Stress with Time
 Compute
Scour Magnitude and Rate
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
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Technical Approach: ISEEP Component
Cone Tip
Rod Sections
Vary Flow RateMaintain Velocity
Coaxial Sheathing
Pump
Controller
Water Tank
Vary VelocityMaintain Flow Rate
Generator
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
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Field Testing
Irene Breach
NC-12 Temporary Bridge
Wake County Bridge
Research Lead  The University of North Carolina at Chapel Hill
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January 31-February 1, 2013
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Isabel Breach
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Field Testing
Kd’ and Pc
GSD of NC-12 Soil
100
90
70
60
50
40
30
20
10
0
10
1
0.1
Pea Island Depth = 0-50 cm
Penetration Rate (cm/s)
Pea Island - Sand
80
% Passing
12
Pea Island - Organic Contents
0.01
10
Pea Island Depth = 50-200 cm
8
R² = 0.6868
6
R² = 0.9658
4
2
Pc
0
10
Grain Size (mm)
Research Lead  The University of North Carolina at Chapel Hill
100
1000
Stream Power (Watts/m2)
10000
CHC-R 5th Annual Meeting
January 31-February 1, 2013
Field Testing and Modeling
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Field Data Reduction
3.5
Assuming an average
flow depth of 0.5 m, a
4.2
m
breach
is
estimated to occur in
approximately 1.5 hours
for a 4 m/s flow velocity
and in 9 hours for 3 m/s
flow velocity
Estimated Erosion Rate (m/hr)
3
2.5
2
1.5
Velocity = 3 m/s
Velocity = 4 m/s
1
0.5
0
0
0.5
1
1.5
Depth of Flow (m)
2
Research Lead  The University of North Carolina at Chapel Hill
2.5
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January 31-February 1, 2013
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Modeling of Flow around Bridge Piers
1.5 m
2.5 m
1m
•
•
•
•
•
3m
24 m
3m
Sand Bed: 24 m long, 20 m wide and 4 m deep
Layers: Two layers soil system
Approach Velocity: 0.45 m/s to 0.9 m/s
Depth of Flow: 1.0 m
Pier Diameter: 1.22 m
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
Pier Scour
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3-D Scour Profile
Research Lead  The University of North Carolina at Chapel Hill
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January 31-February 1, 2013
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Bridge Scour: Empirical Equations
Reference
Equation
Shen et al. (1969)
ds = 0.000223 (Vb/υ)0.619
Breusers et al. (1977)
ds /b = f(V/Vc)(2tanh(y/b))KsKtheta
Jain and Fischer
(1979)
ds /b = 1.86(y/b)0.5(Fr – Frc)0.25
Fr = Froude number
ds/b= 2KsKthetaK3K4(y/b)0.35Fr0.43
K3= factor for mode of sediment
transport, K4 = factor for armoring by
bed material
Richardson and Davis
(1995)
Research Lead  The University of North Carolina at Chapel Hill
Comments
V = flow velocity, υ = kinematic
viscosity of water = 1 × 10-6 m2/s
f (V/Vc) = 0, V/Vc≤0.5
=(2V/Vc-1), 0.5<V/Vc≤1
= 1, V/Vc>1
Vc = Critical velocity, Ks = shape
factor, Ktheta = inclination factor
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Scour Depth / Pier Diameter
Bridge Scour: Empirical Equations
1.8
1.5
ISEEP
1.2
FLOW-3D
0.9
Shen et al. (1969)
0.6
Jain and Fischer (1979)
0.3
Richardson and Davis (1995)
0
0
200
400
600
800
Stream Power (Watt/m2)
Research Lead  The University of North Carolina at Chapel Hill
1000
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January 31-February 1, 2013
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Laboratory Experiments
&
Field Testing
Yulian A. Kebede
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
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Lab Testing with Clay-Sand Mixture
Dry weight of mixture: 10% Fines - 90 % sand
Initial water content : 18 % - 23 %
Dry unit
weight
(kN/m3)
Mean
Undrained
Particle
Shear
Diameter, Strength,
d50 (mm)
Cu (kPa)
17.7
Research Lead  The University of North Carolina at Chapel Hill
0.26
5-8
Liquid
Plasticity
Limit,
Index, PI
LL
20
0
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Penetration rate (cm/s)
Lab Testing Results
•
3.5
3
2.5
2
1.5
1
0.5
0
Run time = 15s
Run time = 30s
Run time = 45s
Run time = 60s
10
100
Stream Power (Watts/m2)
kd
0.017 cm/sec per N/m2 (45 sec)
0.015 cm/sec per N/m2 (60 sec)
• Pc
16 Watts/m2
• Vc
0.32 m/s
• tc
1.75 Pa
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
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• Flow Velocity range of 1.0 m/s to 2.0 m/s
(Froude number 0.23 to 0.45)
• Pier Diameter = 1 m
• Depth of flow = 2 m
Ansari et al. (2002)
dsmc/dsms = 1.51(C*/φ*)0.2
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
22
ERDC Collaboration: Lake Calumet Testing
• Located at far south side of
Chicago, IL
• Largest body of water in the
city
• Highly contaminated due to
years of industrial waste and
runoff from nearby land fills
• Contains an approximate
water depth of 4 ft with a
clay layer located about 1cm
beneath the water depth
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
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Plan
• Collaboration with ERDC in effort to
compare and contrast results with
that of the Erosion Function
Apparatus (EFA)
– EFA testing lead by Dr. Joseph Gialani
• Scheduled to take place in
March/April
• ISEEP testing will be performed onsite
and the EFA testing will collect sample
and perform testing in a nearby
testing facility
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
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Next Steps
Validation Modeling of Various Hydraulic Structures resting on
soils with fine contents and Storm Conditions
Incorporation of skin friction factor to the data reduction
scheme especially at greater penetration depths.
Extend the collaboration work from the lab to the field by
performing field tests at sites where scour rates have been
established in the past
Process the testing approach and the data reduction scheme
for acceptance as ASTM standards
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
25
Milestones
 Modeling of various types of hydraulic structures
resting and assessing applicability of ISEEP for
assessment of scour magnitude
Viability of the approach in various types of soils,
including soil with fine contents
 The refinement of the data reduction scheme with
incorporation of factors such as the rods’ skin
resistance especially at greater penetration depths
 Applicability of the results in view of other existing
approaches that require soil sampling
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
26
End Users and Translation Activities
 Federal Emergency Management Agency (FEMA)
 U.S. Army Corps of Engineers (USACE)
 State Offices and Agencies of Emergency Management
 State Offices of Dam Safety
Standardization of the testing process and data reduction scheme ,
and submission to Committee D18.02 on “Sampling and Related
Field Testing for Soil Evaluations” for review and commenting.
The system is available now and the plan is to test it in cooperation
with ERDC CHL as outlined in the proposal.
Transition of ISEEP to government and private sector via
commercialization processes –Discussion on incubator for a
private company, North Carolina State University office of
Technology Transfer.
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
27
Products
Media Publicity
 Gizmag, November 2010 “Safer levees and bridges thanks to new erosion and scour detector”
 ASCE Civil Engineering Magazine, August 2011-Technology Section, Page 40 “Probe Reveals Hidden Potential of
Scour,”
Conference Proceedings
 Cary Caruso and M. A. Gabr (2010)“In Situ measurement of the scour potential of non-cohesive sediments (ISEP)”
Geotechnical Special Publication No. 211, American Society of Civil Engineers (ASCE), pp. 115-125.
 Cary Caruso and M. A. Gabr (2011) “In Situ Assessment of Scour Potential with Depth Using Jetting Approach,”
Geotechnical Special Publication No. 211, (ASCE), pp.1483-1492.
 M. Kayser and M. A. Gabr (2013). “Scour assessment in cohesive soil using ISEEP.” Accepted, International Conference
on Soil Mechanics and Geotechnical Engineering, Paris, France, 2013.
Posters
 Caruso, C. W., Poster Presentation at DIEM meeting with DHS Under Secretary of S&T , Chapel Hill, NC, Feb 2011.
 Caruso, C. W, DHS University Summit Student Day, Washington, DC, Mar., 2011.
 Kayser, M. and Gabr, M. “Scour Assessment of Bridge Foundations Using an In Situ Erosion Evaluation Probe
(ISEEP)” 92nd Transportation Research Board meeting, Washington DC, January 2013.
Journal Papers
 Gabr, M. A., Caruso, C. W., Key, A., and Kayser, M. “Assessment of In Situ Scour Profile in Sand using a Jet Probe,”,
Journal paper accepted by ASTM, Geotechnical Testing, in press.
 Kayser, M. and Gabr, M. A. “Scour Assessment of Bridge Foundation Using In Situ Erosion Evaluation Probe (ISEEP).”
Journal paper accepted by the Journal of the Transportation Research Board, in press.
Masters Thesis and Masters Project
 Cary Caruso “In Situ Measurement of the Scour Potential of non-cohesive Sediments “ MS thesis, August , 2011
 Austin Key “ Data Reduction Protocol for Assessment of Erosion Parameters Using ISEP ,” MCE Project. January 2012
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013
28
Thank You
Questions?
Research Lead  The University of North Carolina at Chapel Hill
CHC-R 5th Annual Meeting
January 31-February 1, 2013