1. Experimental Investigation of
Debris Motion in Tsunami-Like
Flow Conditions
Jacob Stolle
M. A.Sc. Candidate
Academic Supervisor:
Prof. Ioan Nistor
Thesis Defense
May 24th, 2016
2. Presentation Outline
• Introduction
• Literature Review
• Experiment
• Debris Tracking Methods
• Experimental Results
• Conclusions
• Work in Progress
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
geol105naturalhazards.voices.wooster.edu
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3. Introduction
• Occurrence of several tsunamis
over the past decade:
– 2004 Indian Ocean
– 2010 Chile
– 2011 Tohoku
– 2015 Chile
• Critical infrastructure unprepared
for extreme loading conditions.
• Existing building codes do not
account for loadings and effects
generated by tsunamis (Nistor and
Palermo, 2014).
Introduction
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
Phuket Island, Thailand (Nistor and Palermo, 2014)
Hakozaki, Japan (Yeh et al., 2013)
4. Tsunami Loads and Effects
• Current research has identified
six loads (Yeh et al., 2014):
– Hydrostatic
– Hydrodynamic
– Buoyant
– Surge
– Breaking Wave
– Debris
• Debris can have a variation of
loads on structures (Robertson et
al., 2008):
– Debris Impact
– Debris Damming
Introduction
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
2011 Tohoku Tsunami (courtesy of Dr. Nistor)
2010 Chilean Tsunami (Nistor and Palermo, 2014)
5. Literature Review
• Debris motion very difficult to
evaluate:
– Random nature of debris
motion (Matsutomi et al.,
2008; Matsutomi, 2008).
– Many variables influence
debris motion
(hydrodynamics, debris type,
surrounding environment)
(Naito et al., 2014).
• Current available guidelines
focus on single debris impact
(FEMA P55 and FEMA P646).
Literature Review
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
• ASCE7 – Chapter 6: Tsunami
Loads and Effects (2016)
identify area of influence.
Debris Dispersal Calculation (Naito et al, 2014)
6. Experimental Investigation of Debris Motion
• Probabilistic Approach
– Matsutomi (2008)
𝐾 𝑦 𝑥, 𝑦 =
1
2𝜋𝛿 𝑦
exp
−
𝑦 − 𝑦 2
2𝛿 𝑦
2
– Yao et al. (2014)
• Evaluation of intermediate
variables.
– Reuben et al. (2015)
Literature Review
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
Function of:
• Debris Size
• Debris Geometry
• Hydrodynamics (Froude)
7. Experimental Investigation of Debris Impact Forces
Contact-Stiffness
• Used in FEMA P646.
• Considers the debris velocity,
mass and geometry.
𝐹𝑖𝑚𝑝𝑎𝑐𝑡 = 𝑢 𝑚𝑎𝑥 𝑘𝑚(1 + 𝑐)
Impulse-Momentum
• Used in ASCE7 – Chapter 6.
• Considers debris velocity,
orientation, mass, geometry, and
impact duration.
𝐹𝑖𝑚𝑝𝑎𝑐𝑡 = 𝐶0 𝑢 𝑚𝑎𝑥 𝑘𝑚
𝑡𝑖𝑚𝑝𝑎𝑐𝑡 =
2𝑚𝑢 𝑚𝑎𝑥
𝐹𝑖𝑚𝑝𝑎𝑐𝑡
Literature Review
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
𝐹𝑖𝑚𝑝𝑎𝑐𝑡 - Impact force [N] 𝑘 - Stiffness of debris [N/m]
c - Hydrodynamic mass coefficient 𝑚 - Mass of debris [kg]
𝑢 𝑚𝑎𝑥 - Maximum velocity of debris
[m/s]
𝑡𝑖𝑚𝑝𝑎𝑐𝑡 - Impact duration [s]
𝐶0 - Coefficient of Orientation
8. Objectives and Novelty
Long-term Objective
• Probabilistic investigation of
multiple debris impacts in
tsunami-like flow conditions.
Short-term Objectives
• Develop and validate a non-
invasive debris tracking
methods.
• Evaluate debris entrainment
and motion to identify high-
risk areas in tsunami-like flow
conditions.
Novelty
• Focused on the validation of the
ASCE7 – Chapter 6 standard in
an experimental setting.
• Evaluation of multiple debris
transport in tsunami-like flow
conditions.
• Development of novel debris
tracking methods.
Objectives and Novelty
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
10. Hydrodynamics
• Froude similitude
• Important Variables
(prototype)
– Off-shore Wave Height =
0.12 m (4.8 m)
– Off-shore Flow Velocity =
0.82 m/s (5.19 m/s)
– Surge Height at Debris
Site = 0.08 m (3.20 m)
– Bore Front Velocity at
Debris Site = 2.8 m/s
(17.71 m/s)
Experimental Results
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
11. Experimental Protocol
• Evaluate the effect of:
– Number of Debris
– Initial Orientation
• On:
– Longitudinal Displacement
– Spreading Angle
– Peak Velocities
Variable Variation
Number of Debris 1
3
6
9
18
Orientation of Debris Long
Axis
0o
90o
Distance from Apron Edge 0.23 m
1.81 m
Experiment
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
12. “Smart” Debris
• 1:40 Length Scale
• Ability to track the debris with 6
degrees-of-freedom.
• Bluetooth Low Energy (BLE)
Tags
• Inertial Measurement Units
(IMU)
Debris Tracking Methods
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
13. “Smart” Debris Dry Tests
Debris Tracking Methods
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
Direction Standard Error
[m]
X 0.05
Y 0.06
Z 0.10 - 0.41
Direction Standard Error
[m]
X 0.06
Y 0.08
14. Object Tracking
• Image Processing Algorithm
• Adapted from image
processing problems.
Debris Tracking Methods
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
15. Object Tracking Accuracy
Debris Tracking Methods
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
16. Debris Motion
• Evaluate the relative
repeatability of the debris
trajectories.
Experimental Results
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
Number of
Debris
Standard
Deviation
in X [m]
Standard
Deviation
in Y [m]
Standard
Error [m]
Standard
Deviation in
Orientation
[o]
1 0.030 0.102 0.042 15.05
3 0.045 0.120 0.095 21.60
6 0.049 0.219 0.11 17.05
18. Debris Longitudinal Displacement
Experimental Results
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
Naito et al. (2014)
Number of Debris
Longitudinal
Displacement
19. Debris Spreading Angle
Experimental Results
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
Naito et al. (2014)
20. Conclusions
• The “smart” debris system can provide
high quality information in 5DOF.
– Work is needed to improve the vertical
positional accuracy of the system.
• The object tracking algorithm can
quickly and accurately track up to six
debris.
– Improvements are needed related to
debris agglomeration
• Debris entrainment and motion showed
good repeatability, in which many
variables contribute to the overall
motion of the debris.
• Debris motion dependent on the
interactions that occur either:
– Debris-Debris
– Debris-Ground
• Naito et al. (2014) a conservative
estimate of debris dispersion.
– Further work is needed to establish
effects of macro-roughness.
Next Steps
• A systematic experimental
program of the dependent variable
would allow for a probabilistic
evaluation of debris motion
– Significantly improve estimation
of at-risk areas for debris impact
– Provide a benchmark for future
numerical modelling.
Conclusions
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
21. Work in Progress
• Evaluation of the effects of
hydrodynamics conditions on
debris entrainment and motion.
• Evaluation of debris impact
forces on structures.
• Extension of debris tracking
techniques for the wider field of
coastal and hydraulic
engineering.
Work in Progress
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
22. Acknowledgments
• Waseda University (Tokyo, Japan) for the use of their Tsunami Wave
Basin.
• The International Collaboration between the University of Ottawa,
Waseda University, National Research Council, and University of
Hannover made possible by NSERC Discovery and EU Marie-Curie
Grants.
• Dr. Nils Goseberg for his extensive and continuing support and
guidance throughout this project.
Acknowledgments
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
23. Thank you! Any Questions?
Acknowledgments
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
24. References
Esteban, Miguel, Hiroshi Takagi, and Tomoya Shibayama, eds. Handbook
of Coastal Disaster Mitigation for Engineers and Planners. Butterworth-
Heinemann, 2015.
Haehnel, Robert B., and Steven F. Daly. "Maximum impact force of
woody debris on floodplain structures." Journal of Hydraulic
Engineering 130.2 (2004): 112-120.
Matsutomi, Hideo, Midori Fujii, and Takeshi Yamaguchi. "Experiments
and development of a model on the inundated flow with floating bodies.“
Proceedings of the 31st International Conference on Coastal Engineering,
ASCE. Vol. 2. 2009.
Matsutomi, Hideo. "Method for estimating collision force of driftwood
accompanying tsunami inundation flow." Journal of Disaster
Research 4.6 (2009): 435-440.
References
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
25. References (continued)
Naito, Clay, et al. "Procedure for site assessment of the potential for
tsunami debris impact." Journal of Waterway, Port, Coastal, and Ocean
Engineering 140.2 (2013): 223-232.
Nouri, Y., et al. "Experimental investigation of tsunami impact on free
standing structures.“ Coastal Engineering Journal 52.01 (2010): 43-70.
Rueben, M., et al. "Optical measurements of tsunami inundation and
debris movement in a large-scale wave basin." Journal of Waterway, Port,
Coastal, and Ocean Engineering 141.1 (2014): 04014029.
Yao et al. "A Preliminary Laboratory Study of Motion of Floating Debris
Generated by Solitary Waves Running up a Beach." Journal of
Earthquake and Tsunami 8.03 (2014): 1440006.
Yeh, Harry, et al. "Tsunami loadings on structures: review and
analysis." Coastal Engineering Proceedings 1.34 (2014): 4.
References
Experimental Investigation into Debris Motion in Tsunami-Like Flow
Conditions
