Analysis
Analysis
of
of
Reinforced
Reinforced
Concrete
Concrete
Structures
Structures
Subjected
Subjected
to
to
Blast
Blast
Loading
Loading
S.
S.
Karapinar
Karapinar
, I.
, I.
Sanri
Sanri
, G. Altay
, G. Altay
Workshop Prague, March 30
Workshop Prague, March 30


31, 2007
31, 2007
COST Action C26
COST Action C26
Aim
Aim
of
of
the
the
Study
Study
Analyze
Analyze
the
the
structures
structures
under
under
the
the
effects
effects
of
of
blast
blast
loading
loading
.
.
Including
Including
;
;
the
the
threat
threat
definition
definition
,
,
blast
blast
wave
wave
parameters
parameters
,
,
dynamic
dynamic
properties
properties
of
of
materials
materials
and
and
damage
damage
assessment
assessment
.
.
Definition of Blast Loading
Definition of Blast Loading
Blast loading may result from the detonation of high
Blast loading may result from the detonation of high
explosives, chemical ammunitions.
explosives, chemical ammunitions.
Type of extraordinary dynamic load and it has to be
Type of extraordinary dynamic load and it has to be
described by two parameters; peak overpressure
described by two parameters; peak overpressure
and duration.
and duration.
Blast loading is a function of : Distance of the
Blast loading is a function of : Distance of the
structure from the explosion, and the charge weight
structure from the explosion, and the charge weight
or a weapon size.
or a weapon size.
Formation
Formation
of a
of a
Blast
Blast
Wave
Wave
Variation of pressure within a shock wave (
Variation of pressure within a shock wave (Fertis,1973, Dynamics
And Vibration Of Structures)
Threat
Threat
Definition
Definition
Charge Weight
Charge Weight
or
or
weapon size (W) :
weapon size (W) :
W is expressed in weight or
W is expressed in weight or
mass of TNT
mass of TNT
; the equivalent W of any other explosive material is
; the equivalent W of any other explosive material is
based on experimentally determined factors or the ratio of its
based on experimentally determined factors or the ratio of its
heat of detonation to that of TNT.
heat of detonation to that of TNT.
Stand
Stand


off
off
Distances
Distances
(R) :
(R) :
R measures how close to the building a
R measures how close to the building a
bomb could explode and is therefore a function of the physical
bomb could explode and is therefore a function of the physical
characteristics of the surrounding site.
characteristics of the surrounding site.
General
General
Overview
Overview
of
of
Blast
Blast
Loading
Loading
Dynamic
Dynamic
Behaviour
Behaviour
of
of
Material
Material
Under
Under
Blast
Blast
Loading
Loading
When
When
the
the
concrete
concrete
is
is
strained
strained
;
;
The
The
resistance
resistance
increases
increases
linearly
linearly
with
with
deflection
deflection
until
until
the
the
reinforcing
reinforcing
bars
bars
yield
yield
.
.
The
The
deflection
deflection
is
is
increasing
increasing
but
but
the
the
resistant
resistant
remains
remains
constant
constant
until
until
at a
at a
deflection
deflection
corresponding
corresponding
to
to
a
a
support
support
rotation
rotation
of 2
of 2
°
°
At a
At a
deflection
deflection
corresponding
corresponding
to
to
a
a
value
value
of
of
about
about
4
4
°
°
the
the
element
element
will
will
lose
lose
its
its
structural
structural
integrity
integrity
and
and
fail.
fail.
Dynamic
Dynamic
Strength
Strength
Increase
Increase
Effects of strain rate on stress
Effects of strain rate on stress


strain curve for concrete
strain curve for concrete
(
(
Ref
Ref
: TM 5
: TM 5


1300)
1300)
Dynamic
Dynamic
Increase
Increase
Factor
Factor
(DIF)
(DIF)
DIF is
DIF is
equal
equal
to
to
the
the
ratio
ratio
of
of
the
the
dynamic
dynamic
material
material
strength
strength
to
to
static
static
strength
strength
.
.
DIF is a
DIF is a
function
function
of;
of;
Static
Static
material
material
strength
strength
:
:
If
If
the
the
static
static
strength
strength
of
of
material
material
is
is
high
high
then
then
the
the
increase
increase
in
in
dynamic
dynamic
strength
strength
will
will
be
be
low
low
.
.
Strain
Strain
rate :
rate :
If
If
the
the
material
material
is
is
strained
strained
rapidly
rapidly
then
then
the
the
increase
increase
in
in
dynamic
dynamic
strength
strength
will
will
be
be
high
high
.
.
Deformation
Deformation
Limits
Limits
The
The
controlling
controlling
criteria
criteria
in
in
the
the
blast
blast


resistant
resistant
design
design
is a limit on
is a limit on
the
the
deformation
deformation
or
or
deflection
deflection
of element.
of element.
Two
Two
methods
methods
for
for
evaluation
evaluation
of
of
structural
structural
response
response
:
:
Ductility
Ductility
ratio
ratio
Support
Support
rotation
rotation
Case
Case
Study
Study
The
The
analysis
analysis
of
of
the
the
structural
structural
elements
elements
under
under
blast
blast
loading
loading
with
with
a
a
given
given
charge
charge
weight
weight
and
and
stand
stand


off
off
distance
distance
.
.
The
The
investigation
investigation
of
of
the
the
damaged
damaged
system
system
which
which
contains
contains
the
the
analysis
analysis
of
of
the
the
system
system
with
with
member
member
removed
removed
according
according
to
to
the
the
explosions
explosions
.
.
Analysis
Analysis
of
of
Structure
Structure
under
under
Blast
Blast
Loading
Loading
Charge
Charge
weights
weights
are
are
500 kg , 750 kg , 1000 kg
500 kg , 750 kg , 1000 kg
and
and
1500 kg of TNT.
1500 kg of TNT.
Stand
Stand


off
off
distance
distance
is
is
considered
considered
as 6m.
as 6m.
which
which
is
is
the
the
closest
closest
point
point
to
to
the
the
building
building
according
according
to
to
the
the
plan
plan
configuration
configuration
of
of
the
the
building
building
.
.
Location of explosion to the building
Location of explosion to the building
Blast
Blast
Load
Load
Parameters
Parameters
Blast
Blast
Analysis
Analysis
of
of
Structural
Structural
Frame
Frame
The
The
frame
frame
members
members
on
on
which
which
the
the
plane
plane
is
is
subjected
subjected
to
to
explosion
explosion
directly
directly
are
are
taken
taken
into
into
consideration
consideration
seperately
seperately
.
.
An element
An element
loaded
loaded
by
by
a
a
blast
blast
can be
can be
modeled
modeled
as a
as a
dynamic
dynamic
system
system
with
with
a
a
single
single
degree
degree
of
of
freedom
freedom
correspondig
correspondig
to
to
its
its
mid
mid


span
span
deflection
deflection
.
.
The
The
response
response
of
of
the
the
element is
element is
determined
determined
using
using
ABAQUS,
ABAQUS,
finite
finite
element program,
element program,
which
which
contains
contains
geometry
geometry
and
and
material
material
non
non


linearity
linearity
.
.
view
view
of
of
the
the
x
x


z
z
plane
plane
which
which
is
is
subjected
subjected
directly
directly
to
to
the
the
explosion
explosion
Modelling
Modelling
of
of
the
the
Element
Element
Structural frames are modeled using solid, homogenous
Structural frames are modeled using solid, homogenous
element.
element.
Mesh design is a relatively fine mesh which provides
Mesh design is a relatively fine mesh which provides
moderate accuracy.
moderate accuracy.
The material is concrete (Young’s
The material is concrete (Young’s
modul
modul
us
us
of 28500Mpa and
of 28500Mpa and
Poisson’s ratio of 0,2)
Poisson’s ratio of 0,2)
The plasticity stress
The plasticity stress


strain curve is increased by the D.I.F
strain curve is increased by the D.I.F
The pressure
The pressure


time load values are defined by applying to the
time load values are defined by applying to the
surface of the
surface of the
element.
element.
Blast
Blast
A
A
nalysis
nalysis
of
of
C
C
olumn
olumn
SB121
SB121
S
S
ubjected
ubjected
to 500kg of TNT
to 500kg of TNT
E
E
xplosion
xplosion
W=500 kg of TNT , R=6,16m.
W=500 kg of TNT , R=6,16m.
and
and
Z=0,78 (m/kg
Z=0,78 (m/kg1/3
1/3)
)
P
Pso
so
=1,54
=1,54
Mpa
Mpa
P
Pr
r
=9,405
=9,405
Mpa
Mpa
t
to
o
=0,008
=0,008
sec
sec
.
.
Blast
Blast
loading
loading
of
of
column
column
SB121
SB121
0
2
4
6
8
10
00,0050,01
Time (sec.)
Average pressure (Mpa)
Outside
pressure
inside
pressure
Analysis
Analysis
Result
Result
Max
Max


stress
stress
distribution
distribution
Column
Column
mid
mid


point
point
deflection
deflection
Damage Assessment
Damage Assessment
If the support rotation of the element is exceeded
If the support rotation of the element is exceeded
4
4
°
°
, then it is said to be failed. By this way, three
, then it is said to be failed. By this way, three
models are considered with the member removed
models are considered with the member removed
according to the results are taken from the
according to the results are taken from the
A
A
baqus
baqus
program.
program.
The rest of the system is analyzed according to the
The rest of the system is analyzed according to the
vertical loads by using SAP2000 package program.
vertical loads by using SAP2000 package program.
The
The
n
n
the
the
capacities of the rest of the structural
capacities of the rest of the structural
frames are checked to be the limit
frames are checked to be the limit
or
or
not.
not.
The
The
Analysis
Analysis
of
of
the
the
Damaged
Damaged
System
System
Model 1
Model 1
due
due
to
to
750 kg of TNT
750 kg of TNT
Model 2
Model 2
due
due
to
to
1000 kg of TNT
1000 kg of TNT
Model 3
Model 3
due
due
to
to
1500kg of TNT
1500kg of TNT
Three
Three
damage
damage
scenarios
scenarios
are
are
prepared
prepared
.
.
Damage
Damage
Scenarios
Scenarios
KB122, KZ16,
KN116, KB123,
KZ17, KB124,
KZ18, KN118,
KB137, KZ31,
KB142, KZ36,
KB149
SB120, SZ20,
SB121, SZ21
Model 3
KB122, KZ16,
KB123, KB124,
KZ18, KB137,
KB142
SB121, SZ21,
SB120
Model 2
KB122, KB124,
KZ18, KB142
SB121Model 1
RemovedBeamsRemovedColumns
Damaged
Scenario
Model
Model
3
3
P
P


M interaction of column SN121, SN221, SN321 in
M interaction of column SN121, SN221, SN321 in
y
y


direction
direction
1500,00
1000,00
500,00
0,00
500,00
1000,00
1500,00
2000,00
2500,00
3000,00
3500,00
800,00600,00400,00200,000,00200,00400,00600,00
M (Knm)
P (Kn)
PM interaction
PM interaction
BalanceLimit
SN121
SN221
SN321
Summary
Summary
of
of
Results
Results
KB 119, KB 138, KB141,
KB143, KB121, KB120,
KZ25, KZ32, KZ35, KZ37,
KZ15, KZ43, KN115,
KN125, KN132, KN135,
KN137, KN143, KN217,
KN218, KN225, KN235,
KN237, KN238, KN325,
KN335, KN337, KN343
SN120, SN220,
SN320, SN121,
SN221, SN321
KB122, KZ16,
KN116, KB123,
KZ17, KB124,
KZ18, KN118,
KB137, KZ31,
KB142, KZ36,
KB149
SB120, SZ20,
SB121, SZ21
Model 3
KB 119, KB 138, KB141,
KB143, KB121, KZ32,
KZ35, KZ37, KZ15,
KN116, KN118, KN135,
KN137, KN143, KN216,
KN218, KN235, KN237,
KN238, KN316, KN317,
KN318, KN335, KN337
SZ20, SN120,
SN220, SN121,
SN221, SN321
KB122, KZ16,
KB123, KB124,
KZ18, KB137,
KB142
SB121, SZ21,
SB120
Model 2
KB 119, KB 138, KB141
SB120, SZ20,
SZ21, SN121
KB122, KB124,
KZ18, KB142
SB121Model 1
DamagedBeams
Damaged
Columns
Removed
Beams
Removed
Columns
Damaged
Scenario
Conclusion
Conclusion
According to the results, the system affects significantly when
According to the results, the system affects significantly when
the
the
charge weight increases. But the actual charge weight of explosi
charge weight increases. But the actual charge weight of explosi
ve
ve
used by the terrorist, the efficiency of the chemical reaction a
used by the terrorist, the efficiency of the chemical reaction a
nd the
nd the
source location are not reliably predictable.
source location are not reliably predictable.
The stand
The stand


off distance is the key parameter that determines the
off distance is the key parameter that determines the
blast pressure so for protecting a structure is to keep the bomb
blast pressure so for protecting a structure is to keep the bomb
as
as
far away as possible by maximizing the stand
far away as possible by maximizing the stand


off distance.
off distance.
Blast has a characteristic of high amplitude. The results showed
Blast has a characteristic of high amplitude. The results showed
that
that
if the member subjected to high pressure, they could cause big
if the member subjected to high pressure, they could cause big
deformation on the element and cause to be exceed the support
deformation on the element and cause to be exceed the support
rotation so the elements which are close to explosion are damage
rotation so the elements which are close to explosion are damage
d
d
and failed.
and failed.
THANK YOU FOR
THANK YOU FOR
YOUR ATTENTION
YOUR ATTENTION
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