1. Bridge damage due to earthquake - Asian Institute of...

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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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At 1% Drift

C1 S1

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At 3% Drift

C1 S1

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At 3.5% Drift

C1 S1

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At 8% Drift

S1

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‐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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