Sapienza naito-25-06-13

Sapienza Universita di Roma 6/27/2013
Contact: Clay Naito (cjn3@lehigh.edu) 1
Water-Driven Debris Impact
Forces on Structures:
Experimental and
Theoretical Program
Experimental and
Theoretical Program
Clay Naito, Ph.D., P.E.
Associate Professor of Structural Engineering
Associate Chair of Civil and Environmental Engineering
Lehigh University
Bethlehem, Pennsylvania USA
Research Seminar
June 25, 2013
Sapienza Università di Roma

Presentation Summary
 Lehigh University
 Research Interests – Prof. Naito
 Overview of Collaborative Blast Study
 Overview of Tsunami Demands
 Research Effort on Impact Demands
2

Lehigh University
 Established in 1865.
 Located in Bethlehem, PA
 4700 Undergraduate Students
 2200 Graduate Students
 482 Full Tenure Track Faculty
3

Department of Civil and Environmental
Engineering
 Ranked 17th in the US (US News and World Report)
 Department Organization
 Chair Prof. Panos Diplas
 Associate Chair Prof. Clay Naito
 Areas of Expertise
 Structural Engineering (11 Faculty)
 Hydraulic Engineering (4 Faculty)
 Environmental Engineering (4 Faculty)
 Geotechnical Engineering (2 Faculty)
4

CEE: Structural Engineering
5
John Wilson, Ph.D.
Professor
Dir. of Graduate Studies
Mechanics
Paolo Bocchini, Ph.D.
Assistant Professor
Computational
Mechanics and
Reliability
• Ten Tenure Track Faculty
• 3 Assistant, 2 Associate, 5 Full Professors
• One Professor of Practice – Master of Eng. Program
Jennifer Gross, P.E.
Professor of Practice
Structural Engineering
Stephen Pessiki, Ph.D.
Professor
Fire and Earthquake
Engineering and NDE
Methods
Dan Frangopol, Sc.D.
Professor
Safety and Reliability
Shamim Pakzad, Ph.D.
Assistant Professor
Structural Health
Monitoring and Sensor
Networks
Clay Naito Ph.D., P.E.
Associate Professor
Blast, Impact, and
Concrete Systems
James Ricles, Ph.D.,
P.E.
Professor
NEES Director
Seismic Response and
Retrofit of Steel
Structures
Richard Sause, Ph.D.,
P.E.
Professor
ATLSS Director
Seismic and Blast
Response of Structures
Peter Mueller, Sc.D.
Associate Professor
Concrete Mechanics

Degree Programs
 Bachelor of Science
 Civil Engineering (50 students / yr)
 Environmental Engineering (15)
 Graduate Degrees
 M.S. (13) & Ph.D. (13) Civil Engineering
 Master of Science (19) Structural Eng.
 Ph.D. Structural Engineering (38)
 Master of Engineering Structural Eng.
 Current enrollment 23
 1 year program (June – May)

Research Facilities
7
Fritz Laboratory
ATLSS Research Center

Research Facilities
8
Fritz Laboratory
• 5000 kip (22MN)
Universal Testing
Machine
• Fatigue Testing
Bed
• > 100 years of
experimental
research
• Large scale strong
floor and wall.
• High speed
actuators and DAQ
• Allows for full scale
component and
structure testing.

Research Facilities
9
Advanced Technology for
Large Structural Systems
Sause – Tubular Flange Girder
Ricles – Buckling Restrained Brace Verrazano Narrows Bridge
Deck Replacement - Roy

Throgs Neck Bridge, New York City
Load Testing/Weigh-in-Motion
Infrastructure Deterioration &
Simulation, Measurement, and Evaluation

Department Research Thrusts
11
Infrastructure Reliability,
Maintenance, and Life-
Cycle Management
Infrastructure
Deterioration
Infrastructure Hazard
Mitigation
Intelligent Infrastructure
Simulation,
Measurement, and
Evaluation
Advanced Structural
Materials and Systems

Research Areas
 Hazard Mitigation
 Seismic Mitigation
 Development of a Seismic Design Methodology for Precast Concrete
Diaphragms
 Anti-Terrorism and Force Protection
 Blast Pressure Demands
 Ballistic Fragments – Structures / Personnel
 Close-in Detonation of High Explosives
 Progressive Collapse Design
 Impact Demands from Accidental Impacts
 Debris Loading from Tsunami Events
 Infrastructure Deterioration
 Evaluation and Assessment of Pretensioned Concrete Box Beams
 Use of New Materials – SCC and UHPC
 Implementation of NDE techniques into new construction
12

Infrastructure Deterioration
 Ultimate Strength of Self Consolidating Concrete
Bulb Tee Beams
 Pennsylvania DOT - Inspection Methods &
Techniques to Determine
Non Visible Corrosion of Prestressing Strands
in Concrete Bridge Components
 Federal Highway Administration - Designing and
Detailing Post Tensioned Bridges to Accommodate
Non-Destructive Evaluation

Development of Blast Resistant
Structures (Trasborg / Olmati)
Research Efforts:
 Assessment of Precast Concrete Cladding
 Development of Enhanced Components
Full-Scale Blast Evaluation
Laboratory Static Evaluation
Breach Resistance to Close-in Charges
Wall Cladding Systems
Numerical Modeling

Collaborative Evaluation Effort
15
National Science Foundation (NSF) funded a study by University of Missouri Kansas City
(UMKC) to perform a batch of blast resistance tests on reinforced concrete slabs. The Blast Blind
Simulation Contest is sponsored in collaboration with American Concrete Institute (ACI)
Committees 447 (Finite Element of Reinforced Concrete Structures) and 370 (Blast and Impact
Load Effects), and UMKC School of Computing and Engineering.

Prediction Goal
Given:
• Material Properties
• Blast Demands
• Test Configuration
Determine:
• Displacement time history, maximum and time of occurrence
• Numerical – Crack pattern
Four Categories:
• Normal Strength – Analytical Prediction (SDOF)
• Normal Strength – Numerical Prediction (LS-Dyna)
• High Strength – Analytical Prediction (SDOF)
• High Strength – Numerical Prediction (LS-Dyna)
Research Team Institutions:
Sapienza Università di Roma (SUR), Lehigh University (LU), and
Politecnico di Milano (PM).
Research Team Members: Pierluigi Olmati (SUR), Patrick Trasborg
(LU), Dr. Luca Sgambi (PM), Prof. Franco Bontempi (SUR), and Prof.
Clay Naito (LU).

Shock Tube
17

Video of Test
18

Input Data
19
Normal Slab
37 MPa of concrete strength
GR60 reinforcing steel
Hardened Slab
Vanadium reinforcing steel
0
10
20
30
40
50
60
0 20 40 60 80 100
Pressure[psi]
Time [msec]
PH-Set 2a
PH-Set 2b
Load 1
Load 2
LOAD

Slab Details
20
- 20 March 2013 -

Numerical Modeling
21
Number of nodes: 290628
Number of solid elements: 270960
Number of beam elements: 130
Reinforcements
LS-DYNA

Crack Pattern
Normal Slab
37 MPa of concrete strength / Gr.420 reinforcing steel
LOAD2
LOAD1

Response Estimate
23
Normal Slab
37 MPa of concrete strength / GR60 reinforcing steel
0
1
2
3
4
5
0 0.05 0.1 0.15
δ[inch]
Time [sec]
Load 1 Load 2

Hardened Slab – Crack Pattern
24
LOAD2
LOAD1

Response of Hardened Slab
25
Hardened Slab
Slabs

Results
26
Normal Slab
GR60 reinforcing steel
Hardened Slab
0
1
2
3
4
5
0 0.05 0.1 0.15
δ[inch]
Time [sec]
Load 1 Load 2

Results of Competition
27
Four Categories:
• Normal Strength – Numerical Prediction (LS-Dyna) – 1st place
• Normal Strength – Analytical Prediction (SDOF) – 2nd place
• High Strength – Analytical Prediction (SDOF) – 3rd place (unofficial)
• High Strength – Numerical Prediction (LS-Dyna) – Not released
Upcoming
Presentation – ACI Fall Meeting – Tucson Arizona
ACI special publication
Research Team Institutions:
Sapienza Università di Roma (SUR), Lehigh University (LU), and Politecnico di
Milano (PM).
Research Team Members: Pierluigi Olmati (SUR), Patrick Trasborg (LU), Dr. Luca
Sgambi (PM), Prof. Franco Bontempi (SUR), and Prof. Clay Naito (LU).

Impact from Tsunami Generated
Debris
Research Goals:
 Determine typical debris of concern
 Identify typical spread patterns
 Determine forces generated during
impact

Experimental and
Theoretical Program
Experimental and
Theoretical Program
Clay Naito, Ph.D., P.E.
Associate Professor of Structural Engineering
Associate Chair of Civil and Environmental Engineering
Lehigh University
Bethlehem, Pennsylvania USA
Team: Ron Riggs (U.Hawaii) & Dan Cox (Oregon
State U.)
Research Seminar
June 25, 2013
Sapienza Università di Roma

Tsunami Demands
Inundation Rapid ~ 30 minutes
after event
• Japan
• US Northwest and Alaska

NSF Rapid: Impact of Debris Generated from the Tohoku Tsunami
Field Team:
1.Clay Naito (Lehigh U.)
2.Dan Cox (OSU)
3.Kent Yu (Degenkolb)
4.Daiki Tsujio (Pacific)
5.Prof. Mizutani (Nagoya)
Travel Itinerary:
1.Natori
2.Minamisanriku,
Kesennuma, Rikuzentakta
3.Sendai
4.Onagawa, Ishinomaki
5.Sendai, Natori
2011 Japan Reconnaissance
Overview

Debris and Structural Damage
• Debris Considerations Observed
– Natural and Manufactured Wood
– Vehicle Debris
– Shipping Containers
– Boats/Ships
– Fuel Storage Containers
• Structural System Types
– Reinforced Concrete Buildings
– Steel Buildings
– Wood Frame
– Utility Distribution

Wood Debris
Photo:
Y. Okuda
BRI Japan
Photo: Y. Okuda BRI Japan
Natural Debris
Inundation
Natural Debris
Rundown
Wood Frame Structure Debris Debris Field

Vehicle Debris
Floating Debris
Debris Field
Entry into
buildings
Damming of
Vehicles
Debris Settlement

Boat/Ship Debris Debris Settlement
Contribution to
Tsunami Forces
Vessel Size
Natori
Kessenuma
Impact Forces
Minamisanriku
Ishinomaki
Kessenuma

Shipping Container
Debris Ofunato, Japan
Sendai, Japan
• Container Ports Common
• Containers Float
• Debris in port
• Debris in region

Shipping Containers
Building Impact
Light Pole Impact
Failure Modes
Quantified

Other Debris
Wood Debris
Stairways
Cladding

Fuel Storage Containers
• Failure of Fuel Storage
Containers
• Loss of Anchorage
• Impact damage to
structures
• Fuel containment failure
and contamination to
areas.

Impact Damage

Debris SiteAssessment
Point-source debris
Shipping container yards
Ports with barges/ships
Site assessment procedure
Determine potential debris plan area
Number of containers * area of a container
Define debris concentration: area of debris/land area
2% concentration defines debris dispersion zone

Sendai (Containers)

Natori (Vessel Spread)

Goals of NEES Research Study
Determine the debris impact forces from tsunami
generated debris on structures
Flexible debris
Low velocity, ‘moderate’ mass
Consider fluid effects and (container) contents
Provide relatively simple design formulas
Impact force and duration
Tsunami Loading, Ftotal
+

Longitudinal Impact
Tree, pole or container hitting a column head-on
Column modeled as a massless spring, ks
Transverse Impact
Tree or pole hitting a column transversely
Analytical Models–Wave Propagation
L
ks
x v0
L1
ks
L2
x
v0 ω0

Longitudinal Impact
Rigid impact force:
Duration:
Rigid limit works well
Simplest formula
Transverse Impact
Rigid impact force
Longitudinal impact force is usually larger
Focus on longitudinal impact
Impact Forces
Fl
 E Av0
 kmv0
td
 2L / c0
 2mvo
Fl
0 02 2t shF G Av k mv  

Utility pole
6 m long
Tapered from 0.267 m to
0.216 m diameter
204 kg
About ½ the weight of the
‘basic’ design log of ASCE
7-10 (Flood)
Pendulum test setup
Lehigh In-Air Tests
Load cell down here (not shown)

6.1 m x 2.4 m x 2.6 m and 2300 kg empty
Containers have 2 bottom rails and 2 top rails
Pendulum setup; longitudinal rails strike load cell(s)
ISO 20-ft Shipping Container

Shipping Container Impact

Impact velocity 1.3 m/s
One bottom rail of container hit
Impact Force Time History
0
50
100
150
200
250
300
0 5 10 15 20 25 30
Container
Wood Pole
ImpactForce(kN)
Time (msec)

Impact Force Time Histories
F ≈ 560 kN per m/s
F ≈ 114 kN per m/s

Actual force divided by the analytical impact force
1.0 would mean perfect alignment
Nondimensional Maximum Impact Force

Actual duration divided by the analytical duration
Nondimensional Impact Duration

Large wave flume: 110 m long; 3.7 m wide; 4.6 m deep
1:5 scale container hits column at nearly the flow speed
Multiple water depths and drafts were considered
OSU In-Water Tests

Guide wires controlled the trajectory
Container hits underwater load cell to measure the force
Aluminum andAcrylic Containers
Column and load cell at top of photo

In-air tests carried out with pendulum set-up for baseline
In-water impact filmed by submersible camera
Impact was on bottom plate to approximate longitudinal
rail impact
Impact
In-air impact In-water impact

Insert video
Impact

Side View

In-water impact and in-air impact very similar
Less difference between in-air and in-water compared to
scatter between different in-water trials
Force Time-History

Each symbol style represents unique water depth and
draft combination
Solid black line is the predicted force based on in-air
tests
Maximum Impact Force vs. Speed

Conclusions
Simple formula for design impact forces validated by
experimental data
Assumptions are conservative
Container contents don’t affect impact force
significantly, although duration can be increased
Results indicate fluid doesn’t affect impact force
substantially
Other conservative assumptions compensate for slight
conservatism in ignoring it
Results are the basis for the proposed debris impact
forces in ASCE 7

Acknowledgements
This material is based upon work supported by the
National Science Foundation under Grant No. CMMI-
1041666; REU students supported by Grant No.
CMMI-1005054; Tohoku survey supported by Rapid
Grant No. CMMI-1138668.
Any opinions, findings, and conclusions or
recommendations expressed in this material are those of
the authors and do not necessarily reflect the views of
the National Science Foundation
REU students Amy Kordosky, Patrick Bassal, and
Andrew Lopes helped with the OSU and LU tests.
George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES)

Thank you.

Str
o N
GER
www.stronger2012.com

Sapienza naito-25-06-13

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