Development of a Blast and Ballistic Resistant Insulated Wall Panel. Accidental and intentional detonations of high explosives are an unfortunate reality for not only military facilities, but any building. In the United States, designing for blast loads is required of all military and government structures. Additionally, there has been a recent emphasis on constructing energy efficient, sustainable buildings. Insulated concrete wall panels can meet both requirements due to the blast resistance of reinforced concrete and the thermal properties of the interior insulation layer. This research project focuses on improving the response of an insulated concrete panel to explosions at both larger and small scaled distance, as well as the ballistic resistance of the panel. Emphasis is placed on innovative, emulative reinforcement detailing to improve far scale explosions, while shock resistant materials are utilized within the insulation layer to improve small scale explosions and ballistic response. Static tests are conducted under both point and uniform loading to obtain resistance functions to predict the dynamic response of the insulated panel. Experimental, numerical, and analytical results will be discussed.

1. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 1
Patrick Trasborg, Ph.D. Student – Lehigh University
DEVELOPMENT OF A BLAST AND BALLISTIC
RESISTANT INSULATED WALL PANEL
Advisor: Clay Naito, Ph.D., P.E. – Lehigh University
NSF PD 08‐1637
2013 Sapienza Università di Roma

2. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 2
Background
 BS – Civil/Environmental Engineering Lehigh 2010
 MS ‐ Structural Engineering Lehigh 2012
2
http://www.lehigh.edu/~incee/images/5M%2
0lb.%20Testing%20Machine.jpg
http://lehigh.edu/~incee/images/ATLSS‐Panoramic.jpg

3. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 3
Background
 Currently: Ph.D. Student Lehigh University
 Advisor: Professor Clay Naito
 Project: Development of a Blast and Ballistic
Resistant Insulated Wall Panel
 Importance:
 Blast Design for Occupants’ Safety
 Life Cycle and Sustainability Requirements
3

4. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 4
Overview
 Precast concrete/insulated wall panels
 Far‐field detonations
 Design
 Methods to improve response
 Small panel tests
 Large Panel tests
 Close‐in detonations
 Design
 Numerical models
 Methods to improve response
 Ballistic demands
 Design
 Methods to improve response
4

5. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 5
Precast Concrete
Parking Structures / Office Buildings /
Residential / Manufacturing
Precast Concrete Construction
• Cost Effective
• Energy Efficient
• High Quality
• Rapid Construction
5

6. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 6
Insulated Wall Panel
 Exterior Wythe with Architectural Features
 Insulation Foam – XPS, EPS, PIMA
 Interior Wythe with Wall‐to‐Structure
Connections
 Shear Ties to Connect Interior and Exterior Wythes
6

7. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 7
Overview
 Precast concrete/insulated wall panels
 Far‐field detonations
 Design
 Methods to improve response
 Small panel tests
 Large Panel tests
 Close‐in detonations
 Design
 Numerical models
 Methods to improve response
 Ballistic demands
 Design
 Methods to improve response
7

8. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 8
Blast Design of Concrete Components
8
Far‐field Detonation
Known Threat

9. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 9
Blast Design of Concrete Components
9
Differential Equation of Motion
Approximated as a single degree of freedom (SDOF)
Solve an “equivalent” SDOF system

10. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 10
Development of Resistance Function
10
Idealized RC Resistance Function
Plastic Hinge Formation

11. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 11
Correlating Panel Response to Damage
11
 Defined in terms of:
 Support rotation, θ
 Displacement Ductility, μ
yield
ultimate


yield
ultimate













 
fCSpan
1
tan
Current Response
Limits for Structural
Members

12. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 12
Correlating Panel Response to Damage
12
Defined in terms of:
• Support Rotation, θ
• Displacement Ductility, μ

13. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 13
Overview
 Precast concrete/insulated wall panels
 Far‐field detonations
 Design
 Methods to improve response
 Small panel tests
 Large Panel tests
 Close‐in detonations
 Design
 Numerical models
 Methods to improve response
 Ballistic demands
 Design
 Methods to improve response
13

14. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 14
Small Panel Tests
14
Concentrated Force Concentrated Force
Test Setup Schematic Actual Test Setup Photo

15. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 15
Test Matrix
15

16. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 16
Conventional Panel
16
4'
3"
1'
3" 3"
#3 @ 9" Transverse Reinforcement 9"
LOAD
2'
ELEVATION
PLAN
4'-6"
21
2"

17. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 17
Dogbone Panel
17

18. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 18
Dogbone Properties
18
0
100
200
300
400
500
600
0 0.1 0.2 0.3
SteelStress[MPa]
Steel Strain
Experiment
Model
Dogbone Material Model

19. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 19
Dogbone Panel Analytical Model
19
2 sin
,
2
,
/
/
,
/
/
,
/
/
,
/
/
2 ∗
4

20. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 20
Dogbone Panel Performance
20
0
2
4
6
8
10
12
14
16
18
20
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 5 10
Force[kN]
Load[lbf]
Rotation [deg]
Experiment
Model

21. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 21
Unbonded Panel
21
Teflon Tubing
0
100
200
300
400
500
600
700
800
0 0.05 0.1 0.15 0.2
SteelStress[MPa]
Steel Strain
Experiment
Model
Rebar Material Model

22. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 22
Unbonded Panel Numerical Models
22
Abaqus Model
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0 0.2 0.4 0.6 0.8 1
RebarStrain
Point Along Normalized Panel Length
Bonded
20db
40db
0
0.0002
0.0004
0.0006
0.0008
0.001
0.0012
0.0014
0.0016
0 0.2 0.4 0.6 0.8 1
ConcreteStrain
Point Along Normalized Panel Length
Bonded
20db
40db
At 19.1 mm deflection

23. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 23
Locally Unbonding Reinforcement
23
0
2
4
6
8
10
12
14
16
0 5 10 15 20
Resistance [psi]
Support Rotation [deg]
UFC
Unbond Average
Bar Fracture
Near Elastic‐Perfectly Plastic Behavior

24. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 24
Unbonded Panel Analytical Model
24
compression truss
tension truss: rebar, concrete
rigid link
elastic beam
imposed displacements
unbonded region
k
h
0 5 10 15 20
0
2
4
6
8
10
12
14
16
18
20
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 5 10 15 20
Support Rotation [deg]
Pressure[kPa]
Pressure[psi]
Support Rotation [deg]
Experimental
a1
b2
b1
a2
compression truss
tension truss: rebar, concrete
rigid link
elastic beam
imposed displacements
unbonded region
k
h
pinned link

25. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 25
Unbonded Panel Performance
25
0
2
4
6
8
10
12
14
16
18
20
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 10 20 30
Force[kN]
Force[lbf]
Support Rotation [deg]
Analytical
Experimental
60db
20db
60db
20db
Model does not account for bending stresses
leading to larger error as the deflections increase
Kconc
α
Krebar
Δuu
L1
L
Ld
d
KINEMATICS
B
rigid beams
not in scale

26. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 26
Overview
 Precast concrete/insulated wall panels
 Far‐field detonations
 Design
 Methods to improve response
 Small panel tests
 Large Panel tests
 Close‐in detonations
 Design
 Numerical models
 Methods to improve response
 Ballistic demands
 Design
 Methods to improve response
26

27. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 27
Large Panel Tests
Motivation:
 Scalability of unbonding mechanism
 Influence of shear ties on insulated panel
response
27
Test Setup
Load Cell Hex Nuts
Flate Plate Above and Below
Load Cell for Bearing
6" XX Hvy. Pipe
Hex Nuts - Double Nutted
Frame for Instrumentation
1"Ø B7 Rod

28. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 28
Large Panel Test Matrix
28
http://r2.cygnuspub.com/files/cygnus/image/FCP/20
12/FEB/495x330/xconnector_10626623.jpg
Thermomass – X‐Series
Thermomass –
Composite TieNu‐Tie
Altus Group – C‐Grid

29. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 29
Overview
 Precast concrete/insulated wall panels
 Far‐field detonations
 Design
 Methods to improve response
 Small panel tests
 Large Panel tests
 Close‐in detonations
 Design
 Numerical models
 Methods to improve response
 Ballistic demands
 Design
 Methods to improve response
29

30. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 30
Close‐in Detonation
30
- - f'r <0
No Spall
Spall
Breach
- - f'r >0
Experiment
Front Face
Rear Face
Spall Example
Primary
Mechanisms:
• Spall
• Breach

31. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 31
Close‐in Detonation Design
31
h
R
=
1
a+bψ2.5+cψ0.5
h
R
=
1
a+bψ+cψ2
Spall threshold
Breach threshold
D
R
L
h
Typical cylindrical
cased charge, W
Equivalent
hemispherical
surface charge, Wadj
Concrete wall

32. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 32
Overview
 Precast concrete/insulated wall panels
 Far‐field detonations
 Design
 Methods to improve response
 Small panel tests
 Large Panel tests
 Close‐in detonations
 Design
 Numerical models
 Methods to improve response
 Ballistic demands
 Design
 Methods to improve response
32

33. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 33
Close‐in Detonation Numerical Model
33
•Enhanced performance of
insulated panel to spall/breach
due primarily to gap between
exterior and interior wythes
•Validation of models with
experiments underway

34. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 34
Overview
 Precast concrete/insulated wall panels
 Far‐field detonations
 Design
 Methods to improve response
 Small panel tests
 Large Panel tests
 Close‐in detonations
 Design
 Numerical models
 Methods to improve response
 Ballistic demands
 Design
 Methods to improve response
34

35. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 35
Improving Spall/Breach Response
 Interior hardening methods
 Increase insulation thickness
35
Steel plate, kevlar lining,
composite laminates, etc.
•Currently exploring numerically
and experimentally

36. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 36
Overview
 Precast concrete/insulated wall panels
 Far‐field detonations
 Design
 Methods to improve response
 Small panel tests
 Large Panel tests
 Close‐in detonations
 Design
 Numerical models
 Methods to improve response
 Ballistic demands
 Design
 Methods to improve response
36

37. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 37
Ballistic Design
37
Primary
Mechanisms:
• Spall
• Perforation
Approach for ballistic aspect will be
applying empirical formulas for
reinforced concrete in series
- - f'r <0
No Spall
Spall
Perforation
- - f'r >0
vs
vr
Treat insulation as air gap
v
v =v
s
s r

38. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 38
Ballistic Design
38
Spall Thickness
Tsp= 1.215 Xf d0.1 + 2.12d
Perforation Thickness
Tpf= 1.13 Xf d0.1 + 1.311d
Xf = depth of penetration corrected for concrete strength and fragment material
Residual Velocity
vr =vs [1‐(Tc/Tpf)2]0.555 for Xf <2d
vr =vs [1‐(Tc/Tpf)]0.555 for Xf >2d
UFC 3‐340‐02

39. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 39
Overview
 Precast concrete/insulated wall panels
 Far‐field detonations
 Design
 Methods to improve response
 Small panel tests
 Large Panel tests
 Close‐in detonations
 Design
 Numerical models
 Methods to improve response
 Ballistic demands
 Design
 Methods to improve response
39

40. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 40
Ballistic Response Improvement
 Similar methods as spall/breach panels
 Utilize various ballistic resistant materials such as
UHPC
40
Steel plate, kevlar lining,
composite laminates, etc.
Ultra‐high performance
concrete

41. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 41
Conclusion
 Improving response to far‐field detonations
41

42. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 42
Conclusion
 Improving response to spall/breach and ballistic
threats
42
Steel plate, kevlar lining,
composite laminates, etc.
Ultra‐high performance
concrete
Increased insulation
thickness

43. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 43
Questions?
43
Patrick Trasborg, EIT
pat310@lehigh.edu
Clay Naito, Ph.D., P.E.
cjn3@lehigh.edu
2013 Sapienza Università di Roma
This material is based upon work supported by the National Science
Foundation under Grant No. CMMI‐1030812. 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.

44. Sapienza Universita di Roma 6/27/2013
Trasborg/Naito (cjn3@lehigh.edu) 44
References
 PCI Committee on Precast Sandwich Wall Panels, “State‐of‐the‐
Art of Precast/Prestressed Sandwich Wall Panels”, PCI Journal:
Vol 2, No 2, March 1997
 PCI Blast Resistance and Structural Integrity Committee, “Blast‐
Resistant Design of Precast/Prestressed Concrete Components”,
PCI Report, July 2010
 Department of Defense, “Structures to Resist the Effects of
Accidental Explosions”, UFC 3‐340‐02, 2008, p. 1106
 U.S. Army Corps of Engineers, “Single Degree of Freedom
Structural Response Limits for Antiterrorism Design”, Protective
Design Center Technical Report PDC‐TR 06‐08 – Rev 1, 2008
 Air Force Research Laboratory, “Analytical Assessment of the
Blast Resistance of Precast, Prestressed Concrete Components”,
AFRL‐ML‐TY‐TP‐2007‐4529 Interim Report, April 2007
44

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