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Outline1. Bridge damage to earthquake2. Seismic analysis and evaluation of existing
bridges 3. Bridge strengthening methods4. Cyclic load test of bridge using FRP
strengthening technique5. Strengthening of columns using FRP6. Application of FRC in ductility
improvement of bridge structures
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1. Bridge damage due to earthquake
Potential Earthquake Sources
Indo-Australian plate Eurasian plate
• Megathrust Sunda subduction zone, where Indo-Australian plate moves toward Eurasian plate at a rate of 45-70 mm/year
Tectonic Plate Boundary
• Largest recorded quake is Mw = 9.1 Sumatra-Andaman Earthquake in 2004, a cause of destructive tsunami.
Bangkok
• Generates frequent and large earthquakes.
500-800 km
• Nearest distance from this fault to Bangkok is 500-800 km.
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Potential Earthquake Sources
Crustal Faults
• There are 13 known active faults in Thailand.
Earthquake Sources
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During 1912 to 2007, ~15,000 earthquakes with Mw
≥ 3.0, including foreshocks & aftershocks were recorded near Thailand.
Year Source Location Magnitude Damage
1935 Naan 6.5 Felt in BKK
1975 Taak 5.6
1983 Kanchanaburi(Sri Sawat fault)
5.3,5.9,5.2
1995/96 Chiang Rai 5.1/5.5 Damage to buildings
1995 Phrae 5.2
Earthquakes IN Thailand (Mw ≥ 5) :
Pan Hospital in 1995
Mae Lao Earthquake 5 May 2014
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Masonry infill wall failure
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Bridge pier collapse
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Bridge pier collapse
Unseating
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Unseating
Unseating
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Bridge pier collapse- Flexure failure
Bridge pier collapse- Flexure failure
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Bridge pier collapse- Bar buckling
Bridge pier collapse- Shear failure
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Bridge pier collapse- Shear failure
Joint failure
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Joint failure
Beam failure
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Abutment failure
: Compare structural capacity and demand from earthquake
4 major methods
1. LSP – Linear static procedure2. LDP – Linear dynamic procedure3. NLSP – Non‐linear static procedure4. NLDP – Non‐linear dynamic procedure
2. Seismic analysis and evaluation of existing bridges
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Non‐linear static procedure using CPM
o ตัวอย่างของ Capacity Spectrum Method
Demand vs Capacity
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Bridge evaluation procedure using Capacity Spectrum Method (CPM)
o Analysis for seismic demand from earthquake using Linear Elastic Time History Analysis and convert it into
response spectrum result or “Demand Spectra”
o Calculate structural capacity using pushover analysis method to obtain force-lateral displacement of the bridge
o Compare capacity and demand in the same chart. The seismic resistance capacity of structures could be directly obtained form the chart
Reinforced concrete jacketing
Steel plate jacketing
FRP jacketing - Carbon fiber reinforced polymer (CFRP)- Glass fiber reinforced polymer (GFRP)- Aramid fiber reinforce polymer (AFRP)
3. Bridge strengthening methods
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RC Jacketing
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การเปรียบเทยีบการวบิัตขิองเสาทีม่ีการต่อทาบและไม่ต่อทาบ
VDO\video total Zoom Crack column S1 and S1splice (WMV HD 720 ) NEW.wmv
การวบิัตเิน่ืองจากแรงดดัVDO\S1L WMV HD 720 30p.avi
การวบิัตเิน่ืองจากแรงเฉือนVDO\S3S WMV HD 720 30p.avi
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Steel plate jacketing
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FRP jacketing
What is FRP ?There are three types of fiber1. Carbon fiber reinforced polymer (CFRP)2. Glass fiber reinforced polymer (GFRP)3. Aramid fiber reinforced polymer (AFRP)
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“Stress‐strain relationship of different fiber type”
Advantages:1. Light weight2. Easy to install3. Environmental Durability
Type of CFRP
Disadvantages:1. Expensive2. Fire vulnerability3. Require installation expert
RODPLATESHEET
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Strain
Stress35000 ksc
4000 ksc
Design Stress Limit for CFRP(strain = 0.004)
FRP design for columns
Transverse direction for: - increase compressive strength due to confinement effect
- increase shear strength by truss action
The strength and ductility of concrete will increase when wrapped transversely by CFRP
Longitudinal direction for enhancing moment resisting capacity
It is more effective to increase the confinement when used in circular column compare to rectangular column
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Collapse Behavior of a cylinder wrapped by FRP
Concrete cylinder with compressive strength of 24 MPa
Concrete cylinder wrapped by 1 layer CFRP.Compressive strength 40 MPa
TYPE OF BRIDGE
Pile Bent with 4 columns with
1-layer bracing
4. Cyclic load test of bridge using FRP strengthening technique
Pile Bent with 4 columns with 2-layer bracing
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CLASSIF ICATION OF PILE BENT BRIDGE TYPE
3-span bridge 5-span bridge
EXPERIMENTAL PROGRAM
• Test 4 half-scale model ทดสอบเสา 4 ต้นแบบลดขนาด (half-scale model)
• Strengthening Method
- GFRP- commercially available in Thailand- Use different type of strengthening location
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DETAILING OF BRIDGE SPECIMEN
FOUNDATION OF TEST BRIDGE
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specimen Strengthening Material
Strengthening Approach Test time
C1r_GFRP GFRPP Strengthening after test 1 Month
C2_GFRP GFRP Strengthening before test 1 Month
C3r_GFRP GFRP Strengthening after test 1 Month
C4_GFRP GFRP Strengthening before test 1 Month
TEST BRIDGES
PREVIOUS BRIDGE COLUMN DAMAGE
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STRENGTHENING BY GFRP TYPE1
STRENGTHENING BY GFRP TYPE2
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CONSTRUCTION STAGE
Setup Strain Gauge Longitudinal = 34 Ea.Strain Gauge Transverse = 12 Ea.Total Strain Gauge = 46 Ea.
STRAIN GAGE LOCATIONS
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LVDT LOCATION
Setup LVDT = 20 Ea.
CYCL IC LOAD TEST SETUP
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-3.00
-2.00
-1.00
0.00
1.00
2.00
3.00
0 5 10 15 20 25 30 35 40 45
Drift
(%)
Number of Steps
DISPLACEMENT HISTORY
C1r_GFRP
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Actuator installation
Transverse displacement prevention
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• Sensors
Load cell Displacement sensor
Stain Gage
Reference name of strain gages
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การตดิตัง้LVDT
Measurement of curvature and shear deformation
การตดิตัง้LVDTเพ่ือวัดการเสียรูปเน่ืองจากแรงเฉือนในคาน
Lateral Drift +0.50% Cycle 1
Compressive strength 220‐270 ksc
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Lateral drift +0.75% cycle 1
Lateral drift +1.5% cycle 1
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Lateral force – displacement relationship
STRENGTHENING PROCEDURE FOR CFRP AND GFRP
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1. Grind 4 corner of the columns and beam.
2. Use clean cloth to clean the concrete surface
3. Mix Epoxy Resin using the proper mix ratio according to manufacturing recommendation
3. Use a brush to paint epoxy resin on the target surface
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4. Wrap the fiber and use the roller to roll on the fiber surface to make sure that the fiber perfectly attach to the concrete surface. Paint the fiber with epoxy before wrapping another layer.
Lateral drift +0.50% round 1
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Lateral drift +0.75% round 1
Lateral drift +1.50% round 1
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Lateral drift +3.50% round 1
Lateral force – displacement relationship
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Comparison of Lateral force – displacement relationship
C2_GFRP
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VDO\Pile bent 2 WMV HD 720 30p.wmv
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C3r_GFRP
170 ksc
270 ksc
170 ksc
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VDO\Pile bent 3 Before.mpg
After Strengthening
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VDO\After Repair (Pile Bent3).mpg
C4_GFRP
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150 ksc
150 ksc
150 ksc
VDO\Pile bent 4.mpg
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Durability Proof of GFRP ……………. undergoing research
Durability test of GFRP
MixturesCement Extract
MixturesSodium Hydroxide
(NaOH)
- Weight Loss
- Tensile Strength Loss
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Fiber + epoxy
Steel plate
5 cm
“ Weight Loss Test”
“Tensile Strength Loss Test”
“Tensile Strength Loss Test”
Parameters to be studied- PH of solution- Temperature
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Col. bxh(mm)
Shear Span(mm)
Aspect Ratio
Splice Detailing
AxialLoad Ratio
Mode of Failure
Remarks
S1CFRP 250x350 2050 5.85 No splice 0.2 Flexure GFRP wrap
S1S CFRP 250x350 2050 5.85 25db 0.2 Flexure GFRP wrap
S2CFRP 250x350 1570 4.5 No splice 0.2 Flexure‐shear GFRP wrap
S2S CFRP 250x350 1570 4.5 25db 0.2 Flexure‐shear GFRP wrap
S3CFRP 250x350 1100 3.15 No splice 0.2 Flexure‐Shear GFRP wrap
S3S CFRP 250x350 1100 3.15 25 db 0.2 Flexure‐Shear GFRP wrap
Gravity Load (P)
M
M
V
Contraflexure Point
P
V
h
hH=2.05m
F
P
5. Strengthening of columns using FRP
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6. Application of FRC in ductility improvement of bridge structures
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ObjectiveTo improve the ductility of non-ductile RC columns using steel
reinforced concrete (SFRC)
Test ProgramsC1 – without SFRCS1 – with SFRC 1% by volume
“60mm hook-ended steel fiber”
108
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109 Loading scheme
Test under Displacement Control Condition110
At 0.5% Drift
C1 S1
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111
At 1% Drift
C1 S1
112
At 3% Drift
C1 S1
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113
At 3.5% Drift
C1 S1
114
At 8% Drift
S1
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115
‐100.00
‐80.00
‐60.00
‐40.00
‐20.00
0.00
20.00
40.00
60.00
80.00
100.00
‐9.00 ‐8.00 ‐7.00 ‐6.00 ‐5.00 ‐4.00 ‐3.00 ‐2.00 ‐1.00 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00
Later
al L
oad
(kN)
DRIFT (%)
Column 0.5% FRC
Column S1
Column 1.00% FRC
Hysteresis loop comparison116
Test Results
Column C1 S1
max load, (kN) 58.09 84.30
deflection at yield(mm) 28.79 38.00
load at yield1(kN) 43.57 63.23
deflection at yield(mm) 10.00 12.00
load at failure (kN) 46.47 67.44
deflection at failure (mm) 36.70 72.30
displacement ductility, 3.67 6.03
Mode of failure Flexure Flexure
mPmPmu yPyPyu fPfPfucolPcolPcolu
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เสาท่ีไม่มีการเสริม BRR เสาท่ีมีการเสริม BRR
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ขอบคุณครับ
