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How nuclear weapons harm things.
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Short-DurationDynamics
EXPLOSIONEXPLOSION DAMAGE ASSESSMENT DAMAGE ASSESSMENT
PROF. TED KRAUTHAMMERThe Pennsylvania State University
First Structural Forensic Engineering Seminar onSTRUCTURAL FAILURE INVESTIGATIONS
University of Toronto11-12 January 1999
PennState
OUTLINE
PROBLEM DEFINITION
BACKGROUND
DAMAGE ASSESSMENT TECHNIQUES
COMPUTATIONAL SUPPORT
EXAMPLES
SUMMARY AND CONCLUSIONS
PROBLEM DEFINITION
HOW TO USE EXISTING KNOWLEDGE IN SUPPORTOF:
EFFECTIVE EXPLOSION DAMAGE ASSESSMENTS.
CORRELATING DAMAGE WITH POSSIBLE CAUSES.
ASSESSING THE REMAINING STRUCTURAL CAPACITY.
PROBLEM (Cont.)
TERRORISM
ACCIDENTS
MODERN EXPLOSION DAMAGEASSESSMENT - HALIFAX 1917
6 DEC. 1917: SHIP COLLISION WITHA FRENCH MUNITIONS CARRIER INHALIFAX HARBOUR.
2766 T OF VARIOUS EXPLOSIVES.
OVER 2.5 KM_ OF HALIFAX'SINDUSTRIAL N END WAS TOTALLYLEVELLED. THE BLAST SHATTEREDWINDOWS 100 KM AWAY, AND WASHEARD IN PRINCE EDWARD ISLAND.
1600+ PEOPLE DIED, 9000 INJURED,200 BLINDED BY FLYING GLASS.1600 BUILDINGS DESTROYED,12,000 DAMAGED. TOTAL DAMAGEUS$35 M.
PROBLEM (Cont.)
BUREAU OF ALCOHOL TOBACCO AND FIREARMSU.S.A. CRIMINAL INCIDENTS DATA
1989 - 1993 1991 - 1995
BOMBING INCIDENTS 7,716 8,506
(ATTEMPTED) (1,705) (2,078)
INCENDIARY BOMBING 2,242 2,468
(ATTEMPTED) (557) (782)
DAMAGE (M US$) 641.3 1,257.3
BACKGROUND
BLACK POWDER HAS BEEN USED FORSEVERAL HUNDRED YEARS.
HIGH EXPLOSIVES HAVE BEEN USED FORABOUT ONE HUNDRED AND FIFTY YEARS.
NITROGLYCERINE (1862) - IMMANUEL NOBEL.
DYNAMITE (1875) - ALFRED NOBEL.
NUCLEAR EXPLOSIVES (1945).
BACKGROUND (Cont.)
EXPERIENCE: ACCIDENTS, MILITARY
CONFLICTS AND TERRORISM.
CIVIL WAR, 1861 - 1865 RUSSIA - JAPAN, 1905
WWI, 1914 - 1918 WWII, 1939 - 1945
KOREA, 1950 - 1953 VIETNAM, 1964 - 1975
MIDDLE EAST, 1947 - INT. TERRORISM, 1960s -
CONVENTIONAL NUCLEAR
CHEMICALS AND FUELS. NUCLEAR ACCIDENTS.
VAPORS. NUCLEAR WEAPONS.
COMBUSTIBLE DUSTS.
PRESSURE VESSELS.
EXPLOSIVES.
HIGH EXPLOSIVES.
EXPLOSIVE LOAD SOURCES(MILITARY AND CIVILIAN)
EXPLOSIVE LOAD SOURCES (Cont.)
NUCLEAR DEVICESS
YIELDS: KILOTONS (TACTICAL), OR MEGATONS(STRATEGIC) OF TNT EQUIVALENT.
RELEASE LARGE AMOUNTS OF ENERGY(RADIATION, THERMAL, BLAST, EMP, ETC.) IN~1sec, AFFECTING VAST AREAS.
CONVENTIONAL EXPLOSIVE DEVICES
YIELDS: ~15 TONS OF TNT QUIVALENT.
RELEASE SMALLER AMOUNTS OF ENERGY(BLAST, FRAGMENTS, ETC.) IN ~ 2sec AFFECTINGSMALLER AREAS.
EXPLOSIVE LOADS (Cont.)
EXPLOSIVE LOADS (Cont.)
EXPLOSIVE LOADS (Cont.)
EXPLOSIVE LOADS (Cont.)
EXPLOSIVE LOADS (Cont.)
EXPLOSIVE LOADS (Cont.)
EXPLOSIVE LOADS (Cont.)
200 300 400 500 600 700 800 900 1000 1100 1200
TIME (ms)
0
500
1000
1500
2000
2500
3000
PR
ES
SU
RE
(kP
a)
LOAD COMPARISONS FOR TYPICAL WEAPONS
Mk 84 100m - INCIDENTMk 84 100m - REFLECTED15 KT - INCIDENT15 KT - REFLECTED1 MT - INCIDENT1 MT - REFLECTED
EXPLOSIVE LOADS (Cont.)
200 220 240 260 280 300 320 340 360 380 400
TIME (ms)
0
10
20
30
PR
ES
SU
RE
(kP
a)
LOAD COMPARISONS FOR TYPICAL WEAPONS
Mk 84 100m - INCIDENTMk 84 100m - REFLECTED
TECHNICAL RESOURCES
CONVENTIONAL AND NUCLEAR WEAPONSEFFECTS ARE WELL DOCUMENTED.
NUCLEAR CONVENTIONAL
EARLY: DOD, 1957 NDRC, 1946
RECENT: ASCE, 1985 TM 5-855-1, 1986
Schuster et al., 1987 ESL-TR-87-57, 1989
TM 5-1300, 1990
CONWEP, 1992
TECHNICAL DIFFICULTIES
LOAD DEFINITION: P(x,y,z,t) .
MEDIUM - STRUCTURE INTERACTION.
NONLINEAR DYNAMIC STRUCTURAL BEHAVIOR:
GEOMETRIC.
MATERIAL.
STRUCTURE - CONTENTS INTERACTIONS.
CONTENTS SURVIVABILITY (OR FRAGILITY).
DAMAGE DEFINITIONS.
MANY OF THESE ISSUES ARE NOT WELL DEFINED !
COMPUTATIONAL SUPPORT FORDESIGN AND ASSESSMENT
WEAPON EFFECTS CALCULATIONS.
CLOSED-FORM SOLUTIONS.
SDOF, MDOF (SIMPLE AND ADVANCED).
STRUCTURAL MODELS (BEAM, PLATE, ETC.).
ADVANCED TOOLS (FE, FD, HYBRID, ETC.).
SYMBOLIC AND SYMBOLIC-NUMERIC TOOLS.
SDOF RESPONSE CALCULATIONS
F(t)
M
K or R(x)C
SDOF RESPONSE CALCULATIONS
T / Tn
Xm /
XeFigure 3-54. Maximum deflection of elasto-plastic,one-degree-of-freedom system for triangular load
0.1 1.0 10 1000.1
1.0
10
100 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
0.9
1.0
1.2
1.5
2.0
Numbers next to curves are Ru/P
PRESSURE - IMPULSE DIAGRAM
STRUCTURAL RESPONSE DEPENDS ON td/T
td = DURATION OF THE APPLIED LOAD
T = NATURAL PERIOD OF THE ELEMENT:
T = 2PI/OMEGA, OMEGA = (K/M)0.5
THREE BEHAVIORAL DOMAINS:
td >> T td
PRESSURE - IMPULSE DIAGRAM
1/[XMAX (KM)0.5]
2F /
(KX
MA
X)
DIFFERENT EXPLOSIVE EVENTS CAN BE COMPARED WHENUSING THE CONCEPT OF SCALED RANGE:
l = RW1 3/
8 = SCALED RANGE.R = DISTANCE IN FEET OR METERS.
W = EQUIVALENT TNT EXPLOSIVE WEIGHT, IN POUNDSOR KG.
DAMAGE CAN BE RELATED TO SCALED RANGE.
DAMAGE ASSESSMENT FOR FRAMES
DAMAGE ASSESSMENT FOR SLABS
DAMAGE CRITERIA
ELEMENTTYPE
MATERIALTYPE
TYPE OFFAILURE
CRITERIALIGHT
DAMAGE
MODERATEDAMAGE
SEVEREDAMAGE
Beams ReinforcedConcrete(r >1/2%/face)
GlobalBending/MembraneResponse
Ratios ofCenterlineDeflection toSpan, D /L
4% 8% 15%
Shear Average ShearStrain acrossSection, g v
1% 2% 3%
Steel Bending/Membrane
D /L 5% 12% 25%
Shear D /L 2% 4% 8%
Slabs ReinforcedConcrete(r >1/2%/face)
Bending/Membrane
D /L 4% 8% 15%
Shear g v 1% 2% 3%
Columns ReinforcedConcrete(r >1/2%/face)
Compression Shortening/Height
1% 2% 4%
Steel Compression Shortening/Height
2% 4% 8%
oad BearingWalls
ReinforcedConcrete(r >1/2%/face)
Compression Shortening/Height
1% 2% 4%
Shear Walls ReinforcedConcrete(r >1/2%/face)
Shear Average ShearStrain AcrossSection
1% 2% 3%
ADDITIONAL DAMAGE CRITERIA
DAMAGE VS. SUPPORT ROTATIONS
FOR BEAMS AND SLABS
SUPPORT ROTATION DAMAGE
(DEGREES)
< 2 LIGHT
2 TO 5 MODERATE
5 TO 12 SEVERE
OBSERVED STRUCTURAL DAMAGE
DAMAGE ASSESSMENT
SITECONDITIONS
BACKRAOUNDDATA
EXPERTASSESSMENT
MEASUREMENTSNUMERICALANALYSIS
POSSIBLECAUSE
POSSIBLECAUSE
POSSIBLECAUSE
DETERMINECAUSE
POSSIBLEEFFECTS
POSSIBLEEFFECTS
POSSIBLEEFFECTS
DETERMINEEFFECT
ADVANCED DAMAGE ASSESSMENT
INVESTIGATOR
INTELLIGENT INTERFACE
EXPERT SYSTEM
DESIGNMANUALS
ANDSUPPORT TOOLS
NUMERIC FACILITIESAND
COMPUTER CODES
TEST ANDOPERATIONSDATA BASE
SIGNAL ANALYSIS
SENSORDATA
TOA
A
THE OKLAHOMA CITY BOMBING
19 APRIL 1995
THE EXPLOSIVE CHARGEWAS ESTIMATED BASED ONCRATER DIMENSIONS.
~4000 lbs. TNT EQUIVALENTPLACED ~14 ft. FROM THEBUILDING, 4.5 ft. ABOVEAN 18-in.-THICK PAVEMENT.
EXTENSIVE DAMAGE, FAREXCEEDING WHAT WASSHOWN IN TYPICAL NEWSREPORTS.
THE OKLAHOMA CITY BOMBING
5 6 7 8 9 10
TIME (MS)
0
200
400
600
800
1000
1200
1400
PR
ES
SU
RE
(P
SI)
BLAST LOADING ON COLUMN G24
FRONT
REAR
3 4 5 6 7 8 9 10
TIME (MS)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
LA
TE
RA
L D
EF
LE
CT
ION
(I
N.)
DYNAMIC RESPONSE OF COLUMN G24 AT MIDHEIGHT
FAILURE
DIFFERENTIAL PRESSURE BETWEEN THE FRON AND REAR OFCOLUMN G24 CAUSED ITS FAILURE 3.75 MILLISECONDS
AFTER THE BLAST ARRIVAL.
THE OKLAHOMA CITY BOMBING
DIFFERETIAL UPWARD PRESSURE ON 5TH FLOOR SLAB CAUSEDITS FAILURE LONG AFTER THE BLAST LOADS DIMINISHED.
7 8 9 10 11 12 13 14 15 16 17 18 19 20
TIME (MS)
0
20
40
60
80
100
120
140
160
PR
ES
SU
RE
(P
SI)
BOTTOM
TOP
BLAST LOADING ON 5TH FLOOR SLAB BETWEEN COLUMNS 20 AND 22
0 100 200 300
TIME (MS)
0
2
4
6
8
10
12
DE
FL
EC
TIO
N
(IN
.)
SLAB FAILURE AT 183 MS (8.4 IN.)
PEAK DEFLECTION AT 284 MS (9.3 IN.)
5TH FLOOR SLAB RESPONSEBETWEEN COLUMNS 20 AND 22
THE OKLAHOMA CITY BOMBING
NUMERICALLY SIMULATED EFFECT OF RAPID COLUMN REMOVALON BUILDING BEHAVIOR (Crawford, 1996)
KHOBAR TOWERS - SAUDI ARABIA
EXTENSIVE DAMAGE TOPRECAST APARTMENTBUILDING.
EXPLOSIVE CHARGE WASESTIMATED BASED ONCRATER DIMENSIONS,GLASS BREAKAGE, ANDADVANCED SIMULATIONS.
KHOBAR TOWERS - SAUDI ARABIA
KENYA AND TANZANIA, 1998
PETROCHEMICAL EXPLOSIONS
SUMMARY AND CONCLUSIONS
EXPLOSIVE DAMAGE ASSESSMENT IS DIFFICULT.
EXPERIENCE: EXPLOSION MECHANICS AND EFFECTS
STRUCTURAL MECHANICS AND DYNAMICS
COMPUTATIONAL MECHANICS.
USE DATA TO DERIVE POSSIBLE CAUSE-AND-EFFECTRELATIONSHIPS, AND VALIDATE WITH NUMERICALSIMULATIONS.
ACTIVITIES COULD BE VERY TIME CONSUMING.
URGENT NEED TO DEVELOP INTELLIGENT EXPLOSIONDAMAGE ASSESSMENT TOOLS.