Development of Performance Based Tsunami Engineering PBTE

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Development of Performance Based Tsunami
Engineering(PBTE)

• University of Hawaii at Manoa
• H. Ronald Riggs
• Ian N. Robertson

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Tsunami Research
Fluid-Structure Interaction Scour
Modeling Structural Loading Structural Response
Coastal Inundation
Performance Levels
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Project Team
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Project Team
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Project Team
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Project Team
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Project Team
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Project Team
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Project Team
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Project Team
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Advisory Panel
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Advisory Panel
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Advisory Panel
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OSU Wave Tank Facility
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Technical Areas

• Tsunami bore formation, runup, and coastal
  inundation
• Sediment transport and scour
• Fluid forces on structures
• Structural response, analysis and design

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Runup Experiments and Modeling

• Site-specific bathymetry
• Effect of fringing reefs
• Surface roughness
• Bore formation
• Energy dissipation

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Run-up Experiments

• Tsunami wave basin will be modified to allow for
  three individual flumes with different bottom
  slopes (July - Dec 2007)

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Run-up Experiments-Constant Slope

• Solitary waves with heights at 0.05m increments
  up to 0.65m
• Study bore formation and energy dissipation
• Resistance wave gauges and Acoustic Doppler
  Velocimeters (ADVs) will capture flow velocity
• Benchmark tests for bed roughness, fringing reef,
  scour and structural loading

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Run-up Experiments-Fringing Reef

• Fringing reef will be simulated by curtailing the
  beach slopes at h2, water level, and h2.
• Solitary waves with height at 0.05m increments up
  to 0.65m

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Run-up Experiments

• Laser altimeter will track free surface when air
  entrainment distorts resistance gauges and ADV
  readings.
• Particle Imaging Velocimetry (PIV) will monitor
  transition to white water.
• High speed camera will track markers on still
  water and dry bed.

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Sediment Transport and Scour

• Develop and validate sediment transport
  mechanisms
• Pump up of sediments due to large-scale vortices
  created by bore collapse.
• Entrainment of local sediment by instantaneous
  bed shear stress.
• Enhanced transport due to soil instability
  (momentary static liquefaction caused by high
  pore pressure during drawdown)

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Scour Experiments

• Preliminary scour tests in Large Wave Flume (Fall
  2006)
• Utilize existing sand bed from beach erosion
  experiment

• Velocity measurements using ADVs and PIV
• Sediment concentration using Fiber Optic
  Backscatter (FOBS)
• Pore pressures sensors to monitor soil instability

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Sediment Transport Experiments

• Repeat 110 and 115 bottom slope tests with
  moveable bed
• Well-graded sand bed (0.2mm median grain size)

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Scour Experiments

• Include plexiglass cylinder to simulate pile.

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Fluid Forces on Structures

• Horizontal hydrodynamic loads
• Vertical hydrodynamic loads
• Debris impact loads
• Debris damming loads

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Fluid-Structure Experiments
laser altimeter
high speed camera
piston
absorber
Simple Structure

• Utilize fringing reef setup to produce bore.
• Monitor loading on structural elements and simple
  structural systems

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Fluid-Structure Experiments
laser altimeter
high speed camera
piston
absorber
Shipping Container

• Utilize fringing reef setup to produce bore.
• Monitor loading on structural elements and simple
  structural systems
• Monitor debris damming effects

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Fluid-Structure Simulation

• Use Reynolds Averaged Navier Stokes, RANS fluid
  models with the experimental data to improve
  fluid-structure interaction modeling
• Combination of ABAQUS FLUENT
• Possible use of COMSOL (FEMLAB)

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Structural Response and Design

• Structural response to hydraulic and impact loads
• Progressive collapse prevention
• Prescriptive design
• Methodology for site-specific PBTE

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Performance Levels
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Outreach

• Princeton REU program (summer 06)
• Review of existing design guidelines to protect
  coastal structures against erosion and scour
  damage.
• Assist with design and setup of scour
  experiments.
• Oregon State University
• Web telecast of all experiments performed in the
  TWB.
• Selected experiments will be incorporated into an
  educational webcast for K-12 audience.
• University of Hawaii
• Summer 2006 two High School interns working on
  preliminary FLUENT modeling
• Enhancement of tsunami display at Bishop Museum

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Education and Outreach

• Bishop Museum - Honolulu

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Thank-you!
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