National Business ParkBuilding 300
300 Sentinel Drive
Annapolis Junction, MD
20701
BLAST DESIGN AND
ANALYSIS
Rebecca Dick
Structural Option BAE/MAE
Dr. Memari
Spring 2012 Senior Thesis
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
National Business ParkBuilding 300
•212,000 sq. ft
•Composite steel construction
•7 story office building
•Located in an industrial park in Annapolis Junction,
Maryland
•Cost: $38 Million
•Construction Dates: March 2008-July 2009
N
Thesis Goals
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
•Design a typical bay for blast
•Column, Beam, Girder, Slab, Moment Connection
•Model the redesign In LS-DYNA to verify results
•Use LS-DYNA to show that a partial building model is
sufficient for blast analysis (3 bay by 3 bay, 3
story heights)
•Complete a Site Redesign (Breadth Topic I)
•Complete a Façade Redesign and check heat transfer
through façade (Breadth Topic II)
Site Redesign
#5 @ 18” O.C. EACH
FACE, E.W.
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
N
N
DOWELS TO
MATCH VERT.
(4) #5 SPACED
EQUALLY
Original Site
Redesigned
Site
Blast Load Determination
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
BLAST LOADING
Explosive Compound:
Weight of C-4:
Equivalent
117 Mass
psi for Pressure:
Equivalent Weight of TNT:
R=
C-4
50
1.37
36.5
15
Scaled Distance:
Peak Overpressure:
Peak 21
Reflected
psi Pressure:
4.5
50
117
ft/lb1/3
psi
psi
Reflected Impulse:
Effective Duration:
269
4.6
psi-ms
ms
Gas Pressure Loading Density:
Peak Gas Pressure:
lb
lb
ft
0.0017 lb/ft3
21
psi
Scaled Gas Impulse:
123
psi-ms
Gas Pressure Effective Duration:
25.6
ms
Blast Design
• Consider both impact from the initial blast wave
and additional time-dependent pressures
• Blast assumed to occur at center of bay
• Space will vent at 5 psi
• Limitations on ductility ratio and support
rotations to ensure no connection failures
• Increased yield stresses (71 ksi)
• 1.0B+1.0D+0.25L
Column Design
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
Assumptions:
• Distributed Blast Pressure only on Flange of
Member
• Peak Reflected Pressure (117psi) used to account
for close radius blast load (ie, blast directly next
to column base) and to account for non-linear
loading along column height
• W14x159
Beam and Girder Designs
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
Assumptions:
• Distributed Blast Pressure only on Flange of
Member
• 21 psi Gas Pressure design load- most critical
because long duration
• W27x161 Beam
• W30x116 Girder
Beam Stress Profile
Girder Stress Profile
Slab Design
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
#8 @ 18” O.C.
T&B E.W.
METAL FORM
DECK
(SHORED)
Blast Pressure wave hitting
underside of slab in Lobby Bay
W27x161
BEAM
Assumptions:
•Initial design consisted of slab on shored form
deck, but found to be uneconmical (system depth,
constructability)
•Difficult to design a floor system that is both
economical and sustains little damage
•Slab not a critical element so damage is allowed
(spalling, cracking, failure)
•Final design consisted of 3VLI16 composite deck
with
4.5” concrete
•Research
into topping
Aluminum Foam
Composite
Sandwich Panels
Distribution of Stress in Slab at 15 ms
Moment Connection
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
Assumptions:
• AISC Seismic Design Requirements
• Strong column-weak beam
• Must allow full plasticity of connecting
member to develop
• No overstrength factors for connections
• Reduced Beam Section used to develop
plastic hinge in beam
• 8ES Prequalified Connection
• Blast column determined not to be
sufficient for interior areas due to lack of
strong column-weak beam behavior
Exterior Beam to Column
Moment Connection Location
Reduced Beam Section
LS-DYNA Model
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
Framing of Partial
Model without Slab
Indices Used to Create
Wide Flange Shape
Framing of Partial
Model with Slab
Interior Column with Beams Framing
into it from all sides- Mesh Visible
LS-DYNA Model
Stress over Time
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
Von Mises Stress (psi)
70000
Blast Pressure Wave at
20 ms
60000
Columns
50000
40000
Beams b/t
Columns
Infill Beams
30000
Girders
20000
Slab
10000
0
-10000
0
5
10
15
Time (ms)
20
25
Stress Profiles of all Elements
Modeled at 20 ms
Conclusion
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
•Site redesigned to provide security and safety
•Hand calculations yielded members sufficient to
withstand blast
•Analysis in LS-DYNA proved redesigned structure to
have stresses below dynamic yield
•Analysis in LS-DYNA also showed that blast
pressures not critical in far bays as the
pressure barely reaches adjacent bays so
partial model is adequate
Acknowledgements
•Building
Introduction
•Thesis Goals
•Site Redesign
Breadth
•Blast Design
•LS-DYNA
Modeling
•Conclusion
Thank you to the Penn State Faculty:
A very special thank you Dr. John O. Hallquist, President,
Livermore Software Technology Corporation (LSTC), and
Marsha J. Victory, President, FEA Information Inc, for
providing me access to the LS-DYNA finite element
software for free for my senior thesis and to Gunther
Blankenhorn and Todd P. Slavik for the invaluable
technical support and troubleshooting they provided.
Dr. Memari
Dr. Hanagan
Dr. Parfitt
Ryan Solnosky
Thank you to my friends and family:
David Tran
Brian Rose
Mike Kostick
Ryan Blatz
QUESTIONS?
Hope you had a
blast!!
Façade Redesign
•Designed to resist design wind loads
•Designed using top anchor system and will fail
at 5psi
•Top anchor gaskets and SSG for blast will be
used to hold top in place while other three sides
will be dislodged from mullion supports
•8 mil safety film used to attach glazing to top
anchor at the interior
•Two lites of ¼” Fully Tempered Glass in IGU
Winter Thermal Gradient
Component
R
R
R/RT
Room Air
Inside Air Film
0.68
0.68
1.0
Gyp Board
0.32
1
1.5
Batt Insulation
15
16
24.1
Plywood
0.62
16.62
25.0
Vapor Retarder
16.62
25.0
Air Cavity
0.68
17.3
26.1
Rigid Insulation
11
28.3
42.7
Precast Concrete
0.87
29.17
44.0
Outside Air Film
1.35
30.52
46.0
Outside Air

30.52
Winter Heat Loss
T
70.0
69.0
68.5
45.9
45.0
45.0
43.9
27.3
26.0
24.0
24.0
A=
Uconcrete=
Uglazing=
DTwinter=
DTsummer=
4575 ft2
0.0328
0.3333
46 °F
18 °F
through
concrete
through glazing
sensible heat loss(winter)-=
6895.5
70150
latent heat loss can be neglected due to high efficiency vapor
retarder
Total:
77045.5
Btu/hr
Sensible Heat Gain:
Summer Thermal Gradient
Component
R
R
R/RT
Room Air
Inside Air Film
0.68
0.68
0.3
Gyp Board
0.32
1
0.4
Batt Insulation
15
16
6.8
Plywood
0.62
16.62
7.1
Vapor Retarder
16.62
7.1
Air Cavity
0.68
17.3
7.4
Rigid Insulation
11
28.3
12.1
Precast Concrete
0.87
29.17
12.4
Outside Air Film
1.35
30.52
13.0
Outside Air

30.52
Summer- Heat Gain
T
75.0
75.3
75.4
81.8
82.1
82.1
82.4
87.1
87.4
88.0
88.0
A=
Uconcrete=
Uglazing=
DETD=
DCLF=
IF=
N=
Plights=
Pequipment=
4575 ft2
0.1700
0.81
10
56
1.1
300 people
54600 Btu/hr
9600 Btu/hr
6000 Btu/hr
10000 Btu/hr
2000 Btu/hr
computers
printers
copiers
misc.
Envelope:
Glass:
Outdoor Air:
People:
Lights
Equipment:
2567 Btu/hr
171654 Btu/hr
5033 Btu/hr
69000 Btu/hr
54600 Btu/hr
27600 Btu/hr
Total:
330453 Btu/hr
Total:
66091 Btu/hr
Latent Heat Gain:
Total Summer Heat Gain:
396544 Btu/hr
$# LS-PrePost command file created by LS-PrePost 3.2 (Beta) –
20Nov2011(14:55)
$#
cemptymodel
bmcreate multiple i 1 5 6 7 11 j 1 3 8 13 15 k 1 41 81 121
x -7.30 -0.2425 0.0 0.2425 7.30 y -7.10 -6.320 0.0 6.320 7.10 z 0 180 348 516
bmmovei i 1 5 j 1 5 k 1 4 xyz 0 76 0
bmdeletei i 1 2 j 2 4 k 1 4
bmdeletei i 4 5 j 2 4 k 1 4
bmaccept partid 1
$#
bmcreate multiple i 1 5 6 7 11 j 1 3 8 13 15 k 1 41 81 121
x -7.30 -0.2425 0.0 0.2425 7.30 y -7.10 -6.320 0.0 6.320 7.10 z 0 180 348 516
bmmovei i 1 5 j 1 5 k 1 4 xyz 360 0 0
bmdeletei i 1 2 j 2 4 k 1 4
bmdeletei i 4 5 j 2 4 k 1 4
bmaccept partid 1
$#
8 node solid element with 1
point of integration
Recommended by LSTC
All six components of stress
because continuous element
•Elements created using Block Mesh
•Each member coded individually
•Moment connections modeled using
the Tied Interface Command
•Keycards used to define blast load
•Blast detonated at 2.5ms and model
runs for 20ms
Reinforcement:
Reinforcing Bars
Welded Wire Fabric (WWF)
Lap Splices
Structural Steel:
Grade 50:
All other steel:
Bolts:
Metal Deck:
•Floors:
ASTM A615, Grade 60
ASTM A-185
ACI 318
ASTM A992, Grade 50, Fy= 50 ksi
ASTM A572, Grade 50, Fy = 50 ksi
ASTM A325, with threads included in shear
planes, 1.5” diameter
3VLI16, composite
Minimum Concrete Compressive Strengths (f'c)
Member
28 Day Strength (psi)
Elevated Slabs
4000
Slab-on-Grade
4000
Walls, Piers, and Grade Beams
4000
Interior Concrete Topping
4000
Concrete Exposed to Freezing
4000
Minimum Concrete Compressive Strengths
Live Loads
Superimposed Dead Loads
Area
Floors
Roofs
MEP
Design Load
15 psf
15 psf
20 psf
Area
Floors (including partition
load)
Mechanical Room
Elevator Machine Room
Penthouse Floor
Stairs
Slab-on-Grade
Screen Enclosure and Roof
Area
Design
Load
ASCE 7-05
Load
100 psf
125 psf
150 psf
150 psf
100 psf
150 psf
80 + 20 psf
100 psf
-
60 psf
60 psf
Snow Loads
Load Type
Roof Snow
Load
Drift Load
Design
Load
ASCE 7-05
Load
20
Not
available
17.5
81.94
COST ANALYSIS OF STRUCTURAL MEMBERS
ORIGINAL DESIGN
MEMBER
LENGTH (ft)
NUMBER OF
MEMBERS
W14X99
W14X159*
W27X84
W27X94
W27X102*
15
15
35.1
40.9
40.9
2
2
1
2
3
TOTAL COST PER
LINEAR FOOT
TOTAL W/ O&P (PER
LINEAR FOOT
$
$
$
$
$
$
$
$
$
$
142.02
225.00
120.64
133.64
144.94
158.10
252.00
134.00
149.00
161.00
TOTAL
TOTAL
$ 4,260.60
$ 6,750.00
$ 4,234.46
$ 10,931.75
$ 17,784.14
$
TOTAL W/ O&P
$
$
$
$
$
4,743.00
7,560.00
4,703.40
12,188.20
19,754.70
43,960.95 $
48,949.30
BLAST REDESIGN
MEMBER
LENGTH (ft)
NUMBER OF
MEMBERS
W14X159*
W27X161
W30X116
15
40.9
35.1
4
4
2
TOTAL COST PER
LINEAR FOOT
$
$
$
TOTAL W/ O&P (PER
LINEAR FOOT
225.00 $
225.80 $
164.77 $
TOTAL
% INCREASE FOR REDESIGNED STRUCTURE:
NOTE: Members with (*) were interpolated/extrapolated from data in RSMeans 2012
252.00
251.00
182.00
TOTAL
$ 13,500.00
$ 36,940.88
$ 11,566.85
$
TOTAL W/ O&P
$
$
$
15,120.00
41,063.60
12,776.40
62,007.73 $
68,960.00
141%
141%
A limiting support rotation of 2 degrees, and a limiting ductility
ratio of 10 (whichever governs) are specified as reasonable
estimates of the absolute magnitude of the beam deformation
where safety for personnel and equipment is required. These
deformations are consistent with maintaining structural integrity
into the plastic range.
For a beam element, the ductility ratio must be checked to
determine whether the specified rotation can be reached
without premature buckling of the member.
Under rapidly applied loads, the
rate of strain increases and this has a marked influence on the
mechanical properties of structural steel.
Considering the mechanical properties under static loading as a basis,
the effects of increasing strain rates are illustrated in Figure 5-1 and
can be summarized as follows:
(1) The yield point increases substantially to the dynamic yield stress
value. This
effect is termed the dynamic increase factor for yield stress.
(2) The modulus of elasticity in general will remain insensitive to the
rate of loading.
(3) The ultimate tensile strength increases slightly. However, the
percentage increase is less than that for the yield stress. This effect is
termed the dynamic increase factor for ultimate stress.
(4) The elongation at rupture either remains unchanged or is slightly
reduced due to increased strain rate.
Dusenberry, Donald O. Handbook for Blast-resistant Design of Buildings. Hoboken, NJ: J.
Wiley, 2010. Print.
General Electric. Cnstruction Products. General Electric, 2007. GE Construction Sealants.
GE, 2007. Web. 5 Mar. 2012.
<http://www.siliconeforbuilding.com/pdf/general/GE_Products_Catalogue.pdf>.
Getting Started with LS-DYNA. Livermore, CA, 2002. LSTC. Livermore Software Technology
Corporation, 2002. Web. 26 Dec. 2011.
<http://ftp.lstc.com/anonymous/outgoing/trent001/manuals/gettingstarted/GettingStarted.pdf>.
Limbrunner, George F., and Abi O. Aghayere. Reinforced Concrete Design. 6th ed. Upper
Saddle River, NJ: Pearson Prentice Hall, 2007. Print.
LS-DYNA Aerospace Working Group. LS-DYNA Aerospace Working Group Modeling
Guidelines Document. 2011. Print. Version 11-1.
LSTC. BlockM Multiple Tutorial. LSTC. Web. 22 Dec. 2011.
<http://www.lstc.com/lspp/content/pages/7/blockm/LSPrePost_BlockM_User_Guide_090908.pdf>.
RSMeans Building Construction Cost Data. 70th ed. R.S. Means, 2012. 130-31. Print.
Sriram, Rajan, and Uday K. Vaidya. "Blast Impact on Aluminum Foam Composite Sandwich
Panels." Drop/Impact Simulations. Proc. of 8th International LS-DYNA Users Conference,
Dearborn, Michigan. University of Alabama at Birmingham, 2004. Web. 20 Feb. 2011.
"Standard Practice for Determining Load Resistance of Glass in Buildings." ASTM
International E-1300-04 (2004): 1-58. ASTM International, 2004. Web. 26 Jan. 2012.
"Marylanders Grow Trees." Marylanders Plant Trees. Web. 16 Feb. 2012.
<http://www.trees.maryland.gov/pickatree.asp>.
Stein, Benjamin, John S. Reynolds, Walter T. Grondzik, and Alison G. Kwok. "Thermal
Control." Mechanical and Electrical Equipment for Buildings. 10th ed. Hoboken, NJ: John
Wiley and Sons, 2006. 149-281. Print.
McCormac, Jack C. Structural Steel Design. 4th ed. Upper Saddle River, NJ: Pearson Prentice
Hall, 2008. Print.
US Department of Defence. UFC 3-340-02. US Department of Defence, 2008. 5 Dec. 2008.
Web. 30 Nov. 2011.
Geschwindner, Louis F. Unified Design of Steel Structures. Hoboken, NJ: Wiley, 2008. Print.
Le Blanc, G., M. Adoum, and V. Lapoujade. "External Blast Load on Structure- Empirical
Approach." ALE, FSI, SPH (2). Proc. of 5th European LS-DYNA Users Conference, United
Kingdom, Birmingham. 2005. 2005. Web. 22 Dec. 2011.
<http://www.dynalook.com/european-conf-2005>.
Lee, Dong Kwan (David), and Brendan J. O'Toole. "Energy Absorbing Sandwich Structures
Under Blast Loading." Penetration/ Explosives. Proc. of 8th International LS-DYNA Users
Conference, Dearborn, Michigan. Department of Mechanical Engineering at the University
of Nevada, Las Vegas, 2004. Web. 20 Feb. 2011.
Memari, Ali M., Richard A. Behr, and Paul A. Kremer. "Dynamic Racking Crescendo Tests on
Architectural Glass Fitted with Anchored Pet Film." Journal of Architectural Engineering 10.1
(2004): 5. Print.
Ngo, T., P. Mendis, A. Gupta, and J. Ramsay. "Blast Loading and Blast Effects on StructuresAn Overview." Electronic Journal of Structural Engineering (2007): 76-91. Electronic Journal
of Structural Engineering. The University of Melbourne, Australia, 2007. Web. 18 Dec. 2011.