Maintenance and Repair of Concrete Underwater

Maintenance and Repair of Concrete Underwater

11th INTERNATIONAL OPERATION & MAINTENANCE CONFERENCE
Maintenance and Repair
of Concrete Underwater
May 2013
H.W. Kwon
Contents
1. Introduction
2. Damage and Problems
3. Inspection
4. Repair and Retrofit method
5. Maintenance
Introduction
- All of problems has certain reasons
- It is important to find right reasons through detail
inspection ?
- Repair & rehabilitation method shall be designed
according to inspection results with Life Cycle Cost.
- Maintenance is important to avoid collapse, shut
down and extended service life.
- Case study of Bridges and Marine structures
Damage and Problems
Damage and Problems
- Scaling and Cracks
- Erosion
- Rebar corrosion
- Spalling concrete
- Scour
Damage and Problems
- Rebar corrosion & de-bonded
- Spalling concrete
- Load limitation
Damage and Problems
- Scaling and Cracks
- Rebar corrosion
- Spalling concrete
Damage and Problems
- Twist concrete pier
- Construction Joint Break
- Rebar corrosion
- Scaling
- Cracks
- Gap between concrete
block
Damage and Problems
- Quay Wall Collapse
Inspection method
INITIAL PHASE
Routine inspection
Preliminary inspection
Preliminary desk study
Initial diagnosis
Plan main investigation
Inspection method
DETAIL PHASE
Main investigation
Sampling
In situ
testing
Mapping
study
Laboratory
testing
Appraisal and
evaluation
Structural
assessment/
Design issues
Inspection method
Inspection Equipment & tools
Personnel diving gear
Boat
Underwater light
underwater camera
video
side scan sonar
Inspection method
Visual inspection
NDT
- Video & Photos
- Sampling
- Measurement
- Side Scan Sonar
- Scour
- Rebar Corrosion
- Type of damage
- Size of damage
- Settlement
- Remote camera
Repair and Retrofit method
Material Selection Process
Owner
requirements
Service
conditions
Determine
Project objectives
Causes of
deterioration
Application
conditions
Determine
material properties
needed to meet
project objectives
Identify materials
or systems which
will produce the
required properties
Select material or system
that provides optimum balance of
performance, risk
Repair and Retrofit method
2. Installation cofferdam
1. Design cofferdam
3. Scaling and cracks
4. Rehabilitation
5. After GFRP application
Steel encasement for foundation
Sheet pile protection for foundation
FRP encasement for foundation
Repair and Retrofit method
FRP Application procedure underwater
Repair and Retrofit method
Crack Repair
1. Clean
4. Installation packer
2. Check crack
3. Sealing with UW epoxy
5. Injection UW epoxy
6. Surface grinding
Repair and Retrofit method
Rehabilitation for Erosion and corrosion
1. rebar corrosion
3. FRP form installation
2. Chipping
4. Grouting with
underwater mortar
Repair and Retrofit method
Rehabilitation for Erosion and corrosion
1. Erosion and corrosion problems
3. GFRP application
2. Dry Shotcrete application
4. After coating
Repair and Retrofit method
1. Gap between Concrete blocks
3. Nylon form with underwater mortar
2. Grouting with underwater mortar
4. After
Repair and Retrofit method
프레임
00
500~ 600ver.
20
블럭
2000
【1.프레임 제작】
골재채움 후
수중그라우트재주입
프레임
주입호스
나이론 폼
골재채움용 지퍼
나일론폼
【2.나이론폼 설치】
그라우트재 주입
블럭 침하
주입호스
골재채움
【3.그라우트제 주입】
Repair and Retrofit method
1. Jetty
2. Rebar corrosion
3. Strengthening with GFRP
4. After
Repair and Retrofit method
1. Railway bridges without maintenance
2. Pier #2 was broken by ship
3. Wire-saw underwater cutting
4. After rehabilitation
Repair and Retrofit method
Before
After 1m raised up
Repair and Retrofit method
before
after
Repair and Retrofit method
Rebar & FRP
Form Installation
Grout with Conductive
Mortar
Electrical
connection
Before
Zinc mesh is used
as sacrificial
anode
Repair and Retrofit method
GFRP application
1. Before construction
2. Surface treatment
3. Priming
4. FRP Installation
5. Completion
Maintenance
- It is expected to retain the required levels of its
functions during intended service life.
- Maintenance procedure consist of initial inspection,
deterioration prediction, inspection, evaluation,
assessment, remedial measures and recording.
- Not only the engineering aspect but also social and
economical ones should be required.
- Life Cycle Cost management are expected to be very
effective for maintenance strategy.
Maintenance
Inspection after 4 years GFRP application
Corrosion Monitoring Sensor
Thermocouple
Resistivity probe/
Pseudo-reference electrode
Upper cap
Counter electrode
W
C
①
R
1
②
R
2
T1
T2
③
Grout
Working electrode
A
A
Bottom cap
Resistivity probe
[Section A-A]
① GalvaPulse
corrosion potential (mV)
corrosion velocity (mm/yr)
corrosion resistance (K ohm)
② Nilsson resistance measurement
concrete resistance (K ohm)
③ Multimeter
Temperature (°C)
WWW.CONCLINIC.CO.KR
Hyuck Woo Kwon
+966 2 234 3494
+966 54 382 6777
[email protected]