DAMAGE ASSESSMENT METHODOLOGY DEVELOPED FOR
TCIP Alper Ilki, Omer Halici, Eren Kupcu, Mustafa Comert, Cem Demir
Istanbul Technical University, Civil Engineering Faculty
International Workshop on Advances in Assessment and Modeling of Earthquake Loss, 4-5 November 2019, Istanbul
Contents
• Outline of the Present TCIP Damage Assessment Method
• Literature Review to Check/Update Damage Modifiers
• Repair Methods for Earthquake Damaged Structural Members
• Performance of Earthquake Damaged-and-Repaired Structural Members
• The Damage Threshold for Repairability
• Conclusions and Future Works
2
Contents
• Outline of the Present TCIP Damage Assessment Method
• Literature Review to Check/Update Damage Modifiers
• Repair Methods for Earthquake Damaged Structural Members
• Performance of Earthquake Damaged-and-Repaired Structural Members
• The Damage Threshold for Repairability
• Conclusions and Future Works
3
Outline of the Present TCIP Damage Assessment Method
• Post-earthquake seismic damage evaluation of buildings after a major earthquake can easily become a major challenge since the number of buildings that require damage assessment can reach to tens of thousands
• On the other hand, relatively faster qualitative assessment approaches based on experience of the expert can be biased when combined with the post-eq psychology
• The experts tend to stay on the safe side and designate buildings with heavier than actual damage classes
• The classification of damages in buildings also determines the pace of the recovery stage, overestimation of damage causes loss of time and money
• Thus, an accurate and rapidly applicable quantitative damage assessment method based on measurable parameters is required considering the number of buildings and the insufficient number of qualified inspectors 4
Outline of the Present TCIP Damage Assessment Method • For this purpose, in 2003* (after the destructive 1999 Marmara Earthquakes), a quantitative post-eq
damage assessment methodology was developed for the Turkish Catastrophe Insurance Pool (TCIP, DASK in Turkish),
• The developed TCIP methodology aims to evaluate the damages in reinforced concrete (RC) and masonry structures
• The method was modified in 2015 to include a first quick inspection stage for identifying sligthtly or heavily damaged low- and medium-rise buildings with floor area less than 400 m2
• In scope of the method, the experts of TCIP (who may not be civil engineers if the number of buildings to be investigated is high), visit the building and make observations and measurements from the exterior and interior of the building
* H. Boduroglu, P. Ozdemir, A. Ilki
5
Post-Earthquake Damage Assessment
6
Non-damaged
Cosmetic Damage
Slight Damage
Moderate Damage
Severe Damage
Partial or Total Collapse
Repairable Irrepairable
Building Damage ?
Outline of Present TCIP Damage Assessment Method
7
Unclassified
Heavily Damaged
Exterior Assessment
Slightly Damaged
Moderately Damaged
Severely Damaged
Interior Assessment
Based on Japanese Residual Energy Dissipation Capacity Approach
Outline of Present TCIP Damage Assessment Method
8
Initial Assessment
•Low- and mid-rise buildings that form the majority of all buildings are evaluated •Can be performed by experts who are not civil engineers •Slightly and heavily damaged building will be identified (app. 80-90% of all)
Expert Assessment
• Buildings not categorized in the initial assessment stage are to be evaluated by civil engineers.
Outline of Present TCIP Damage Assessment Method
• Step 1
Check for partial or total collapse
• Step 2
Check if the residual I.D.R. > 0.02
• Step 3
Check if the structure is tilted more than 3° from the base
9
“Heavily Damaged” Yes
“Heavily Damaged” Yes
“Heavily Damaged” Yes
Exterior Assessment
Outline of Present TCIP Damage Assessment Method
10
Damage Type
Residual Crack Width Compression Damage Damage
Modifier Type O - - 0.00 Type A ≤0.5 mm - 0.15 Type B 0.5 mm< w ≤3 mm Cover Crushing 0.35 Type C >3 mm Cover Spalling 0.65
Type D - Buckling of Reinforcement, Core Crushing 1.00
Interior Assessment
Initiate the assessment at the most damaged story
Outline of Present TCIP Damage Assessment Method
11
Interior Assessment
< 400 m2
n < 8 No
Is the plan area ≤ 400m2 and number of
stories above the ground ≤ 8 ?
Yes Is the number of vertical
columns/shear walls with “Type C” and “Type D” damage is greater than 10% of the total number of
vertical members?
No
Yes
Calculate WDR
No
Determine the number of columns and shear walls
at that story
Heavily Damaged
Is the number of vertical column shear walls with “Type B” damage is less than 10% of the total number of vertical members, and the remaining
members are either “Type A” or “Type O”?
Slightly Damaged
Yes
[ ] 1000
00.165.035.015.0×
++++×+×+×+×
=DCBA
DCBAWDR
Outline of Present TCIP Damage Assessment Method
12
Interior Assessment Damage
Type Damage Modifier
Type O 0.00
Type A 0.15
Type B 0.35
Type C 0.65
Type D 1.00 0, A, B, C, D are the total cross-sectional are of the vertical members in the relevant damage type Damages of beams can also be included to be considered if widespread and heavy beam damages are available.
Damage state of structures according to WDR;
0% ≤ WDR < 20% DS1 - ”Slightly Damaged” 21% ≤ WDR < 35% DS2 - “Moderately Damaged” 35% ≤ WDR DS3 - “Heavily Damaged”
Contents
• Outline of the Present TCIP Damage Assessment Method
• Literature Review to Check/Update Damage Modifiers
• Repair Methods for Earthquake Damaged Structural Members
• Performance of Earthquake Damaged-and-Repaired Structural Members
• The Damage Threshold for Repairability
• Conclusions and Future Works
13
Literature Review to Check/Update Damage Modifiers Similar to the Japanese JBDPA (2015) approach the lost energy dissipation capacity is
used for the definition of damage modifiers: 0.15 for A, 0.35 for B, 0.65 for C, and 1.0 for
D member damage classes
14
Load
Displacement
Ed: Dissipated energy Er: Remaining
dissipation capacity
η = 𝐸𝐸𝑑𝑑𝐸𝐸𝑑𝑑+𝐸𝐸𝑟𝑟
Damage modifier is a measure of already dissipated energy as a percentage of total energy dissipation capacity
Literature Review to Check/Update Damage Modifiers In order to check the current modifier value data from 100 column tests compiled from
the literature.
Main difficulty: Crack widths are generally not reported.
Concrete compressive strength <20 MPa 20 MPa - 30 MPa >30 MPa Number of column tests 30 40 30 Axial load ratio < 20% 20%-40% > 40% Number of column tests 55 25 20 Long. Reinf. Ratio <1% 1% - 2% 2% - 4% Number of column tests 34 23 43 Long. bar type Deformed Plain Number of column tests 80 20 Main failure mode Flexural Shear Number of column tests 60 40
Literature Review to Check/Update Damage Modifiers
A B C D
Mean 0.90 0.71 0.60 0.10 St. Dev. 0.07 0.10 0.17 0.07 CoV 0.08 0.15 0.29 0.71 Points belove current value 6 4 5 0
Total number of tests 18 19 67 87
Contents
• Outline of the Present TCIP Damage Assessment Method
• Literature Review to Check/Update Damage Modifiers
• Repair Methods for Earthquake Damaged Structural Members
• Performance of Earthquake Damaged-and-Repaired Structural Members
• The Damage Threshold for Repairability
• Conclusions and Future Works
17
Repairing Methods for EQ Damaged Structural Members
18
Type A
Flexural Crack <=0.5mm
Shear Crack <=0.5mm
Type A Damage
- Remove Concrete fragments - Clean the dust particles inside the cracks with air compressor
Crack width
<0.05mm?
Widen the crack surfaces and patch with non-shrink
grout
Repair completed
Low viscosity epoxy injection Repair completed
Yes
No
Repairing Methods for EQ Damaged Structural Members
19
Type B
Cover Crushing
0.5 mm – 3 mm crack width
Type B Damage
Existence of cover
crushing?
Remove the crushed concrete. Clean and roughen the surface
Repair completed
Is reinforcement
revealed?
Yes Yes
Existence of crack?
No
Yes
The cover concrete needs to be recast (See the procedure
for Type C)
Patching with repair mortar
No
Repair completed
Epoxy injection
Crushing Removing the crushed cover and roughening the region
Patching application with repair mortar
Remove the concrete layer to the one diameter depth
behind long. bar
Repairing Methods for EQ Damaged Structural Members
20
Type C
Cover Spalling
Crack width > 3mm Cover spalling
Type C Damage
Existence of cover
crushing?
Remove the crushed concrete
Repair completed Yes
Existence of crack?
No
Yes
Patch the member with repair mortar
Repair completed
Crack width > 3mm ?
Low viscosity epoxy injection
Medium viscosity epoxy injection
Yes
No
No
Cover spalling Patching with repair mortar
Removing the concrete layer
Repairing Methods for EQ Damaged Structural Members
21
Type D
Core crushing and buckling of reinforcement
Residual shear deformation
Step 1
Present overlapping length
Damaged region
Suspending the structural system with temporary props
Step 2
Removing the crushed concrete in the damaged region and cutting the buckled reinforcement Step 3
Attaching new reinforcement
min 20 Φ
min 50Φ Stirrup spacing smax=100mm
Step 4
Casting concrete
Add the new reinforcement considering the sufficient anchorage and overlapping
length
Repairing Methods for EQ Damaged Structural Members
22
Type D Type D Damage
Remove the damaged concrete and cut the buckled bars
Add stirrups
Repair completed
Core crushing and buckling of reinforcement
Residual shear deformation
Suspend the structure with temporary props
Place the formwork and cast new concrete
1 2
3 4
5
Contents
• Outline of the Present TCIP Damage Assessment Method
• Literature Review to Check/Update Damage Modifiers
• Repair Methods for Earthquake Damaged Structural Members
• Performance of Earthquake Damaged-and-Repaired Structural Members
• The Damage Threshold for Repairability
• Conclusions and Future Works
23
Performance of EQ Damaged-and-Repaired Structural Members
24
Literature Review Test Specimen
Type Repair Method
Reached displacement before repair
(x δy)
Apprx. Secant
Stiffness Ratio after
Repair
Apprx. Ultimate Strength
Ratio after Repair
Approx. Energy
Dissipation Capacity
after Repair
Marder (2018) Beam
Epoxy Inj. and Mortar Patching 3.4 0.88 1.04 Increased
Epoxy Inj. and Mortar Patching 5.4 0.79 1.07 Similar
Epoxy Inj. and Mortar Patching 5.4 0.85 1.07 Similar
Cuevas and Pampanin
(2017) Beam
Epoxy Injection 1.2 1.00 1.05 N/A
Epoxy Injection 2.2 0.90 1.05 N/A
Watanabe et al. (2004) Column
Epoxy Injection 3.0 0.81 1.04 Increased
Epoxy Injection 5.0 0.79 1.05 Increased
Mortar Patching 5.0 0.81 1.07 Increased
Mortar Patching 7.0 0.77 1.06 Reduced
Lehman et al. (2001)
Bridge Column Epoxy Injection 3.5 0.50 1.00 Similar
French et al. (1990)
Interior BC
Assembly
Epoxy Injection 4 0.85 1.01 N/A
Epoxy Injection 4 0.89 1.05 N/A
Lee et al. (1976)
Exterior BC
Assembly
Epoxy Injection 4 0.93 1.28 N/A
Epoxy Injection 4 1.03 1.24 N/A
Celebi and Penzien (1973)
Beams
Epoxy Injection 3.5 N/A 1.11 N/A
Epoxy Injection 4 N/A 1.21 Reduced
Epoxy Injection 4 N/A 1.19 Reduced
Epoxy Injection 5 1.1 1.17 Reduced
Expanded from Marder (2018)
Load
Displacement
K0
KR
Approximated Yield
0,00
0,20
0,40
0,60
0,80
1,00
1,20
1,40
0,00 2,00 4,00 6,00 8,00
Rep
aire
d St
reng
th /
Und
amag
ed S
tren
gth
Maximum Displacement Ductility Prior to Repair
0
0,2
0,4
0,6
0,8
1
1,2
0,00 2,00 4,00 6,00 8,00
Rep
aire
d Se
cant
Stif
fnes
s / U
ndam
aged
Se
cant
Stif
fnes
s
Maximum Displacement Ductility Prior to Repair
Performance of EQ Damaged-and-Repaired Structural Members
25
Literature Review
Columns, further
experimental
study is needed
• Literature survey shows a trend that damaged-and-repaired specimens approximately
exhibit the same strength and ductility but slightly lower stiffness properties than
that of undamaged ones
26
Performance-wise
Load
Displacement
Undamaged
Repaired
Performance of EQ Damaged-and-Repaired Structural Members
Contents
• Outline of the Present TCIP Damage Assessment Method
• Literature Review to Check/Update Damage Modifiers
• Repair Methods for Earthquake Damaged Structural Members
• Performance of Earthquake Damaged-and-Repaired Structural Members
• The Damage Threshold for Repairability
• Conclusions and Future Works
27
The Damage Threshold for Repairability
28
Load
Displacement
Undamaged
Damaged
After Repair?
Performance-wise Cost-wise
Repair Cost
Benefit
Feasibility?
The Damage Threshold for Repairability
Can the repaired structure withstand
the same PGA?
29
Performance-wise
Damage Type Stiffness Modifier
λK
Strength Modifier
λQ
Ductility Modifier
λD
Type A 0.90 1 1
Type B 0.80 1 1
Type C 0.80 1 1
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
0 0,1 0,2 0,3 0,4 0,5 0,6
Sae
& a
(g)
Sd & d (m)
Undamaged
Repaired
The Damage Threshold for Repairability
Three extreme cases have been compared with typical sub-standard undamaged
structures:
• Undamaged structure λK=1 (Effective stiffness)
• All columns λK=0.9 (Type A)
• All columns λK=0.8 (Type C)
• All columns λK=0.7 (for observation)
30
Performance-wise Case Studies
Load
Displacement
KIeff
0
0,2
0,4
0,6
0,8
1
1,2
1,4
0 0,1 0,2 0,3 0,4 0,5 0,6
Sae
& a
(g)
Sd & d (m)
0
0,1
0,2
0,3
0,4
0,5
0,6
0 0,05 0,1 0,15 0,2
Sae
& a
(g)
Sd & d (m)
The Damage Threshold for Repairability
31
Performance-wise Case Studies Structure
Similar PGA capacity with the intact ones
Contents
• Outline of the Present TCIP Damage Assessment Method
• Literature Review to Check/Update Damage Modifiers
• Repair Methods for Earthquake Damaged Structural Members
• Performance of Earthquake Damaged-and-Repaired Structural Members
• The Damage Threshold for Repairability
• Conclusions and Future Works
32
Conclusions
• From the beginning (since 2003), the TCIP Post-EQ Damage Assessment Methodology has
been shaped to allow unbiased and accurate damage categorization of earthquake-stricken
buildings and continue to be developed with the recent site and laboratory observations
• Performance analyses showed that damaged-and-repaired buildings can theoretically have
similar PGA capacity with the intact ones
• Repairability threshold can be correlated with the repair cost rather than the structural
performance of repaired structures
• A link between WDR and repair cost needs to be defined for a clear repairability limit
33
Future Works
• The relationship between the damage state and repair cost (structural +
nonstructural) for Turkey are being investigated:
– Structural analyses
– Statistical data from past eqs
• The seismic performance of damaged-and-repaired RC columns still needs further
research:
– A set of experimental tests will be carried out on repaired RC columns
– Stiffness, strength and ductility modifiers will be updated/validated accordingly
34
Top Related