damage evaluation analysis
TRANSCRIPT
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Hikaru NAKAMURA
Minoru KUNIEDAYoshihito YAMAMOTO
NAGOYA UNIVERSITY, JAPAN
DAMAGE EVALUATION ANALYSIS ANDREPAIR/STRENGTHENING METHOD
OF CONCRETE MEMBERSDUE TO EARTHQUAKE
a .concept 14 : 4 th ASEP22 - 24 M a y 2014Century Pa rk Ho te l M in i la
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CONTENTS
Effect of Big Earthquake fromEconomic point of view
Damage and Restoration Process of
Damaged Concrete Structures
Damage Evaluation using F.E.M
Damage Evaluation using RBSM
Rapid Repair/Strengthening Methodusing UHP-SHCC
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Recent strong earthquakes concretestructures were damaged
1: Kobe, 95.1.17, M7.2
2: Tottori,00.10.6, M7.3
3: Geiyo, 01.5.24, M6.7
4: South of sanriku-oki, 03.5.26, M7.1
5: Miyagi-oki , 03.7.26, M6.2
6: Tokachi -oki , 03.9.26, M8.07: Niigata-ken chuetsu, 04.10.23, M6.8
8: fukuoka-oki, 05.3.20, M7.0
9: Noto Hanto, 07.5.25, M6.9
10: Niigata-ken chuetsu-oki,
07.7.16, M6.611: Iwate-Miyagi nair iku, 08.6.14, M7.2
12: Higashi Nihon, 11.3.11, M9.0
After Kobe Earthquake, the concrete structures have beendamaged due to several earthquakes in Japan.
map of recent strong earthquakes that concrete structures were damaged
13
4
5
6
2
8
7109
11
It is difficult to avoid damage of concrete structures perfectly due to strong earthquake.We have to consider the influence of damage of concrete structures.
12
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Change of number of dead persons andeconomy loss
Change of Economic Loss and Casualities by E.Q. Disasters in the World
0
100,000
200,000
300,000
400,000
500,000
600,000
1900-
1909
1910-
1919
1920-
1929
1930-
1939
1940-
1949
1950-
1959
1960-
1969
1970-
1979
1980-
1989
1990-
1999
2000-
2005
0
10
20
30
40
50
60
70
80
us$ Billions
EconomylossDearthperson
Dearthperson
Economy
loss
Economy loss increase from 1970. This is the reason that society develop highly and social system connect
with many parts. If once some parts of social system break, it influence to total system and economy loss.
Important point is to decrease economy loss in order to keep social
system as well as to decrease number of dead persons.
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Economy loss forecast due tofuture earthquakes
Probability map of earthquake
Economy loss
(trillion US$)(direct damage)
Probabilityduring 30years
Inland
earthquake inTokyo
112(6.7) 70%
Tokai,Tonankai and
Nankaiearthquake
2.2(1.7)
70%
Economy loss forecast and occurrence probability
Direct damage
Indirect damageDecrease of damage
Rapid Restoration
Damage prediction and evaluation are important
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CONTENTS
Effect of Big Earthquake fromEconomic point of view
Damage and Restoration Process of
Damaged Concrete Structures
Damage Evaluation using F.E.M
Damage Evaluation using RBSM
Rapid Repair/Strengthening Methodusing UHP-SHCC
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Seismic Performance
SeismicPerformance 1
Function of the structure during an earthquake is maintained,and the structure is functional and usable without any repairafter the earthquake.
SeismicPerformance 2
Function of the structure can be restored within a short periodafter an earthquake and no strengthening is required.
SeismicPerformance 3
There is no overall collapse of the structural system due to anearthquake even though the structure does not remainfunctional at the end of the earthquake.
Seismic performance is classified into 3 cases
The damage is allowable for strong earthquake.Performance 1 : serviceabilityPerformance 3 : safetyPerformance 2 : serviceability and restoration ability
from social and economic points of view
Concept
make clear damage for restoration process
definition of seismic performance in JSCE specification.
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The severe damages were observed in 5 onestory RC viaduct of Tohoku Shinkan-senconstructed in 1977 to 1978.The feature of damages was that the endcolumns are mainly damaged. The endcolumns failed in shear with the spalling of
the cover concrete.
Damage of columns of RC elevated bridges of Shinkan-sen due toSouth of Sanriku-Oki Earthquake at 2003
damaged one story 4 spans RC elevatedbridges of Shinkan-sen
Damage and Restoration Process
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Restoration procedure was (1) injection of epoxy resin to cracks, (2)
restoration of cross section by shrinkage compensating mortar, and(3) steel jacketing.
Restoration finishedonly in 3 days
May 26: earthquake occur
May 27: shinkan-sen start to drive slow speed
May 29: shinkan-sen drive normal speed again
process of repair and strengthening of damaged structure
Damage and Restoration Process
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In the case, the damaged structures were strengthened by RC jacketingafter restoration of cross section.
Tokachi-Oki Earthquake on September 26, 2003
Damage and Restoration Process
The spalling of the concrete cover and buckling of the longitudinal
re-bars occurred at cut-off plane of the longitudinal re-bars.
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Damage of Shinkansen bridge due to Higashi NihonEarthquake
Restoration procedure was (1) chipping of cover concrete around spalling part,(2) arrangement injection tube, (3) arrangement web reinforcement, (4)
restoration of cross section by shrinkage compensating mortar, and (5)injection of resin to cracks
Restoration finished only in 8 days
Spalling of cover concrete at cut-off plane
Damage and Restoration Process
the restoration ability is very
important based on social and
economic points of view
how to verify the damage for
restoration ability before
earthquake and how to restore inshort time after earthquake
http://www.jreast.co.jp/e/index.htmlhttp://www.jreast.co.jp/e/index.html -
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CONTENTS
Effect of Big Earthquake fromEconomic point of view
Damage and Restoration Process of
Damaged Concrete Structures
Damage Evaluation using F.E.M
Damage Evaluation using RBSM
Rapid Repair/Strengthening Methodusing UHP-SHCC
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Damage Evaluation using F.E.M
In Past
two decades
constitutive
models
numerical
algorisms
analytical
theories and modeling
Nonlinear analysis, especially
F.E.M for concrete structureshas advanced remarkably
Nonlinear analysis, especially F.E.M. become
a most powerful tool to verify
the required performance of concrete structures
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Evaluation of Seismic Performance
Floor
Footing
Shaking Table
Spring
Dynamic test for 5 stories
RC building0 2 4 6 8 10 12 1
-1.2
-0.8
-0.4
0
0.4
0.8
1.2
Time [sec]
Accelerator[g] V03S02 [1.35g]
Max. Acc. is about 1.0g
simulation result of dynamic test for 5stories RC bui ld ing in order toevaluate the seismic performance
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Results of F.E.M
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Can nonlinear analysis simulate damage?
Compression failure of concrete
Buckling of re-bars
Typical damage in flexure
Damage Local behavior
Localized area
Local strain
Can nonlinear analysis simulate local behavior ?
we can simulate global structural behavior using nonlinear analysis
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10 20 30 40 50 60
20
40
60
80
0
Displacement (mm)
Load(kN)
10 20 30 40
100
200
0
Displacement (mm)
Load(kN)
-0.0794-0.0588-0.0382
0.0030-0.0176
-0.1000-0.0308-0.0216-0.0124
0.0060-0.0032
-0.0400
B series
Compressive strain distribution Compressive strain distribution
A series
Problem of F.E.M
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CONTENTS
Effect of Big Earthquake fromEconomic point of view
Damage and Restoration Process of
Damaged Concrete Structures
Damage Evaluation using F.E.M
Damage Evaluation using RBSM
Rapid Repair/Strengthening Methodusing UHP-SHCC
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RBSM (Rigid Body Spring Model)
This model can evaluate the effect of
bending and torsional moment
automatically without rotational springs.
Vertex
Gravity pointIntegral point
For reduction of
elements dependency
One integral point hastwo kinds of springs
(normal/shear)
Cracks are expressed by the failure of
springs and cracking behavior can be
shown directly.
Analytical model is
divided by 3-D Voronoi
particles
A number of springs are set inboundary of each surface.
RBSM is analytical model to simulate structural behavior by springsbetweenRigid Bodies.
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Concrete Material Model
Concrete Models (Yamamoto et al. 2008)
no softening part
is modeled in
compression
kn k t
kn k t
Normal spring
Shear spring
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Reinforcement Model
Reinforcement : beam element
beam nodes : attach to the concrete particlesthrough zero-size link element
stress strain relationship : bi-linear model.
Bond property: introduced into the shear springof linked element
fy
fy
Stress strain relationship
Zero sizelinkelement
Beamelement
modeling of reinforcement
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Results of RBSM
(b) 2700kN
0.01mm 0.1mm
0 2 4 6-2
-1
0
1
2
Time (s)
Displac
ement(mm)
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Uni-axial Compression Test
Strain distribution along the height and deformation
(The strain distributions are measured by using acrylic bar arranged inside specimen)
Uni-axial Compression test carried by
Fujikake et al. having diameter of 100mm
and height of 200mm and 400mm aresolved by RBSM.
Reasonable simulation of axial local strain and localized area with failure mode.
0.002 0.004 0.006 0.008 0.
10
20
30
40
50
0
Stress(N/mm2)
Strain
Analysis (200mm height)test (200mm height)Analysis (400mm height)
test (400mm height)
Stress-Strain relationship
a
b
c
d
a b c dTest Analysis
5000 10000 15000
100
200
300
400
0
Distancefromb
ottom(mm)
Local strain ()
1.0max
0.8max
0.6max
0.4max0.2max
5000 10000 15000
100
200
300
400
0
Distancefromb
ottom(mm)
Local strain ()
1.0max
0.8max
0.6max
0.4max
0.2max
The stress strain relationship agree
significantly well with the test for different
shape.
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Damage evaluation of Flexure Failure Beam
Analytical model with Voronoi diagram
Load displacement relationship
20 40 60
10
20
0
Load(kN)
Displacement (mm)
Test Analysis
d
c
d
c
PC barcantilever type RC beam failed in
compression flexural mode
Results of canti lever type RC beam failed in compression flexural mode
Crack propagation behavior at peak and post peak
RBSM can simulate global behavior,
the advantage is that it can show the
realistic crack propagation behavior
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RBSM is useful method to simulate local damage of concrete structures
as well as cracking
Flexure Failure test of Beam
Longitudinal compressive strain distributions at failure zone
(a) Test result
strain
0 100 200 300 400 5000
5000
10000
15000
0 100 200 300 400 5000
5000
10000
15000 0.7Pmax
Location (mm)
strain
Location (mm)(b)Analytical result
0.8Pmax
0.9Pmax
PmaxPmax
0.9Pmax0.8Pmax0.7Pmax Similar
strain
distribution
Pmax 0.8Pmax (Post-peak) 0.6Pmax (Post-peak)
Deformation in compression failure zone Realistic failure behavior
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Damage Evaluation under Cyclic Loading
600150
640 110
[Unit:mm]
115
200160
600 640 110
Skeleton curve
Dimension of simulated RC column
Analyt ical model
0 5 10 150
10
20
30
[mm]
[kN]
Displacement (mm)
Load
(kN)
3y
The feature of the specimen is shear
failure after yielding of longitudinal re-
bars. This type of failure is often
observed with diagonal cracks in the
case of lower web reinforcement
subjected to cyclic loading.
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Simulation Results of RC Column
flexural behavior is dominant
1y
2y
3y
-30-25-20-15-10 -5 0 5 10 15 20 25 30-30
-20
-10
0
10
20
30
[mm]
[kN]
Displacement (mm)
Load
(kN)
monotonic(analysis)cyclic (analysis)test
Diagonal crack develop
Shear deformation is dominant withreduction of load carrying capacity
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-20 0 20-30
-20
-10
0
10
20
30
[mm]
[kN
]
Simulation Results of RC Column
Displacement (mm)
Load
(kN
)
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Effect of Web Reinforcement
-20 0 20-30
-20
-10
0
10
20
30
displacement[mm]
load[kN]
Displacement (mm)
Load
(kN
)
The shear failure after yielding can be
prevented by arrangement of sufficient
amount of web reinforcement.Design code require suff icient amount
of web reinforcement in order to fail in
flexural.
Web reinforcement of 0.46%
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CONTENTS
Effect of Big Earthquake fromEconomic point of view
Damage and Restoration Process of
Damaged Concrete Structures
Damage Evaluation using F.E.M
Damage Evaluation using RBSM
Rapid Repair/Strengthening Methodusing UHP-SHCC
Requirement of Rapid
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Requirement of Rapid
Repair/Strengthening Method
Disadvantages;
Much cost Many construction processes
Development of Rapid Recovery Technique
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Development of Rapid Recovery Technique
by using repair material, UHP-SHCC
Process of repair for damaged structures
Damaged part of
concrete structure. Very easy.Spraying UHP-SHCC only! !
Advantages:
Without any other construct ion processesand heavy construction machine
No addit ional reinforcement
No framework
No additional cross section
Cementitious material is easy to stock and repair
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Ultra High Performance-Strain Hardening Cementitious Composites
What is the UHP-SHCC ?
PE fiberSilica fume water cement Fine aggregate
Cement Silica sand
PE fiberSilica fume
High strength
High ductili ty
High permeabil ity
Wh i h UHP SHCC ?
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Multiple fine cracking.
What is the UHP-SHCC ?
Compressive strength (MPa) Tensile strength (MPa)
UHP-SHCC 80~90 7~8
Normal Concrete 25~35 2~3
0
2
4
6
8
10
12
14
0 1 2 3 4 5
Strain(%)
Stress(MPa)
Increase fiber content
Crack width is less than 0.05mm
strengthening material
Wh t i th UHP SHCC ?
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What is the UHP-SHCC ?
Penetration of chlor ide ion after specimens merged
in salt water of 10%(EPMA)
UHP-SHCC normal concreteW/C=56%
mm2mm
W/B is about 20%
Mixing of silica fume
High permeabil ity
Repair material with coating effect
Wh t i th UHP SHCC ?
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What is the UHP-SHCC ?
Spraying method
Reduce construction work
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Initial loading
Treatment
Repair
Second loading
Curing
Flow of experiment.
A cyclic loading (namely initial loading)
was carried out for RC column designed
by Japanese code.
450 450400
22@80=1760
850
850
4
00
2500
40040
4@80=320
Cross Section
Longitudinal Reinforcement
Hoop Reinforcement
(Unit:mm)
Axial Loading(1N/mm2)
Outline of experimental specimen
Procedure of Experiment
f
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Initial loading
Treatment
Repair
Second loading
Curing
Flow of experiment.
Concrete structure was damaged.
(Spalling of cover concrete andbuckling of longitudinal reinforcementwere observed).
Spalling of cover concrete.
Buckling of longitudinal
reinforcement.
Procedure of Experiment
P d f E i
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Treatment
Repair
Second loading
Curing
Flow of experiment.
Spalling of cover concrete. Cleaned up!!
Concrete brocks were cleaned up by hand
work and water spraying was also appliedto prevent the water absorption of repair
material itself.
Init ial loading
Procedure of Experiment
P d f E i t
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Init ial loading
Treatment
Repair
Second loading
Curing
Flow of experiment.
UHP-SHCC: Spraying technique. PCM: Plastering technique.
(most popular to repair)
Three repair materials were used.
Spraying technique
UHP-SHCC
Plastering technique.
PCM
Procedure of Experiment
P d f E i t
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Init ial loading
Treatment
Repair
Second loading
Curing
Flow of experiment.
Curing days of repair materials
and repaired specimens:
5~10 daysVery short!!
RAPID RECOVERY TECHNIQUE!!
Procedure of Experiment
Load Displacement Curves
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Load- Displacement Curves
-150 -100 -50 0 50 100 150-250-200
-150
-100
-50
0
50100
150
200
250
Displacement (mm)
Load(kN)
Initial loading
PCM specimen-150 -100 -50 0 50 100 150-250-200
-150
-100
-50
0
50100
150
200
250
Displacement (mm)
Load(kN)
Initial loadingUHP-SHCC specimen
PCM specimen: Peak load and ductility were lowerthanthat of init ial loading.
UHP-SHCC specimen: Peak load and ductility were
higher than that of init ial loading.
PCM specimen UHP-SHCC specimen
F il B h i (S d L di )
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Failure Behavior (Second Loading)
Front view (Final) Side view (Final)
(PCM) (UHP-SHCC)
Front view (Final) Side view (Final)
Spalling of PCM
Splitting cracks along longitudinal reinforcements
PCM specimen (second loading)
UHP-SHCC specimen (second loading)
NOT spalling of UHP-SHCC!
NOT splitting cracks along longitudinal reinforcements!
CONCLUSION
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CONCLUSION
It is difficult to avoid the damage of concrete structures
due to big earthquake. Therefore, the damage should beevaluated directly by the analysis to verify the restoration
ability from social and economic points of view.
Requirement against advanced nonlinear analysis is tosimulate local behavior reasonably as well as global
behavior such as load displacement relationship.
As an advanced simulation method, the applicability ofRigid-Body-Spring Model (RBSM) was presented. It
showed high potential to simulate the realistic behavior of
concrete structures directly such as local damage as well
as load-displacement relationship until failure stage.
CONCLUSION
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CONCLUSION
The rapid jacketing technique was developed which
involves only spraying of UHP-SHCC. Any formwork andadditional reinforcement are not required. It might be helpful
to reduce a construction process that is corresponding to
reduction of cost.
It was confirmed experimentally that the developedtechnique using UHP-SHCC improve not only ultimate load
but also ductility of recovered specimen. It seems that the
prevention of buckling of longitudinal reinforcement, which
was constrained by UHP-SHCC, imparts the mechanical
improvement to the column specimens.
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Thank You Very Much
for Your kind Attention !