strength and ductility of axially loaded rc short column confined with cfrp and gfrp haider osamah...
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STRENGTH AND DUCTILITY OF AXIALLY LOADED RC SHORT COLUMN CONFINED WITH CFRP AND
GFRP
Haider Osamah Al-KaraghoolSupervised by: Dr. Adil K. Al-Tamimi
Dr. Jamal A. Abdalla
Thesis Defense
OUTLINE
• Introduction
• Research Objectives and Significance
• Literature Review
• Experimental Program
• Discussion of Results
• Conclusion
Introduction
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
The need for safe building!!!
Construction Industry vs. Technology
• Dead Load, Live Load, Load path, New building requirements
Change in the structure
• Corrosion, Fatigue, Design Errors, Hazardous Factors
Degradation of a structure
New Building vs. Old Buildings
Environ. Friendly
Energy Conservative
Less Carbon Footprint
Enhanced Life Expectancy
Introduction Fiber Reinforced Polymer (FRP)-Defenition
A composite material made of a polymer matrix reinforced with fibres.
Types
AFRP
CFRP
GFRP
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Introduction Fiber Reinforced Polymer (FRP)-Properties
Criterion Aramid Carbon Glass
Young Modulus Good Very Good Adequate
Tensile Strength Very Good Very Good Very Good
Compressive Strength Inadequate Very Good Good
Long-term Behavior Good Excellent Very Good
Stiffness Good Very Good Adequate
Fatigue Behavior Good Excellent Adequate
Bulk Density Excellent Good Adequate
Alkaline Resistance Good Very Good Inadequate
Price Adequate Adequate Very Good
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Introduction Fiber Reinforced Polymer (FRP)-Properties
Material Density (kg/m3) Tensile Modules (GPa) Tensile strength (MPa)
AFRP 1050-1250 20-125 1000-1800
CFRP 1600-1900 120-250 1200-2250
GFRP 1600-1800 20-55 400-1800
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Introduction Fiber Reinforced Polymer (FRP)-Advantages
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Advantages
CFRP GFRP
High Tensile strength Low cost
High Tensile modulus High tensile strength
High fatigue resistance High chemical resistance
High insulation
Introduction Fiber Reinforced Polymer (FRP)-Disadvantages
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Disadvantages
CFRP GFRP
High cost Low Tensile Modulus
High brittleness High hardness
High conductivity Low fatigue resistance
Low abrasion resistance
Research Objectives
• Study the behavior of Normal designed RC column when strengthened
with CFRP or GFRP in one or two layers.
• Study the behavior of Under designed RC columns when strengthened
with CFRP or GFRP in one or two layers
• Compare the behavior of strengthened under designed RC columns with
the non-strengthened normal designed RC column.
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Research Objectives
• Strength (Load Capacity)• Ductility
Behavior as
• Type of Material• Number of Layers
Parameters involved
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Research Significance
Testing strengthened RC column with CFRP or
GFRP
Find the ideal solution that would replace the idea of the demolishing
the structure
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Literature Review
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
A. Mirmiran, M. Shahawy, M. Samaan, H. El Echary, J. C. Mastrapa, and O. Pico (1998)
Studied the effect of Shape, Length, and Bond between the concrete and the
jacket.
Eccentric Loading
More than 100 samples were casted (Cylinders and Square columns)
GFRP
Conclusion
Square sections are less effective than Circular sections
Effect of length–to-diameter ratios within the range of 2:1 and 5:1 is not significant
for either strength or ductility of the section
Adhesive bond does not effect load-carrying capacity of FRP-confined concrete.
Literature Review
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
P. Rochette and P. Labossiere (2000)Studied the behaviour reinforced concrete columns reinforced confined with
compositesAxial LoadingMore than 40 specimensCFRP and GFRP
ConclusionConfinement of Circular is more effective than Square and Rectangular.The Radius of the round corner is directly proportional with the effective of the
confinement. Excessive confinement will lead to very sudden and destructive compressive
failure, which must be avoided.
Literature Review
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Omar Chaallal, Mohsen Shahawy, and Hunzer Hassan (2003)Study the effectiveness of external wrapping for concrete columns Parameters involved:
Concrete strengthAspect ratio of cross sectionNumber of FRP layers
Axial LoadingSquare and Rectangular sectionCFRP30 samples
Conclusion CFRP confinement showed improvement in strength and ductilityCompressive strength is inversely proportional with the axial and transverse strain.the gain in the compressive strength depends on the ratio of the stiffness of the
FRP jacket in the lateral direction to the axial stiffness of the column
Literature Review
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Hua Wei, Zhimin Wu, Xia Guo, and Fumin Yi (2009)Investigate the mechanical behaviour of columns with partial deteriorated strength
and to evaluate the availability of the partial confinement.Parameters involved:
Concrete strengthNumber of wrapping layersPlain vs. Reinforced concrete
Axial LoadingSquare sectionCFRP30 samples (15 Plain vs. 15 Reinforced)
Conclusion Partial confinement in deteriorated regions with CFRP can significantly enhance the
performance of columns.The ductility of confined specimens was enhanced significantly compared to the
partial deteriorated column as well as the original column.
Experimental Setup
Theoretical Analysis
Concrete Mix Design
Strain Gauge Fixing
Epoxy Preparation
Column Preparation
Proposed Matrix
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Experimental Setup Theoretical Analysis
ACI 318
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Experimental Setup Theoretical Analysis
ACI 318
Gross Area (150x150 mm) 22500 mm2
Steel Area (4 #10) 1257 mm2
Concrete Compressive Strength (28 Days) 35 MPa
Steel Yield Strength 420 MPa
Strength Reduction Factor (ties) 0.85 -
Load 790 kN
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Experimental Setup Theoretical Analysis
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Normal Design Under Design
Experimental Setup Theoretical Analysis
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Normal Design Under Design
Experimental Setup Theoretical Analysis
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Experimental Setup Concrete Mix Design
ACI 211
Material Cement Water Coarse Aggregate Fine Aggregate
Ratios 1 0.46 1.6 2.91
S.G 3.14 1 2.61 2.57
Water Absorption Coarse Aggregate
Fine Aggregate
Percentage 0.5 1.0
Aggregate Coarse Fine
Material 20mm 10mm Crushed Sand Dune Sand
Percentage 60 40 65 35
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Experimental Setup Concrete Mix Design
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Experimental Setup Strain Gauge Fixing
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Experimental Setup Epoxy Preparation-Primer
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
• Low-viscous material used to fill the
pores on the concrete specimen
surface in order to ensure full bonding
between the FRP composite and the
concrete surface
• Two parts : Part A : Base
Part B : Hardener
Experimental Setup Epoxy Preparation-Primer
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Property Test Method Value
Component - Two:Part A-base
Part B-Hardener
Form - Liquid
Color - Clear I Pale Yellow
Potlife - 70+/- 10min
Service Temperature - +5 Co to +75 Co
Surface Drying Time ASTM D2939 6-8 hours
Bond Strength ASTM D4541 Concrete Failure
Experimental Setup Epoxy Preparation-Saturant
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
• Medium-viscous material used as a
bonding agent between the concrete
surface and the FRP material
• Two parts : Part A : Base
Part B : Hardener
Experimental Setup Epoxy Preparation-Saturant
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Property Test Method Value
Component - Two:Part A-Base
Part B-Hardener
Form - Liquid
Color - Grey/White/Light Blue
Potlife - 45-60 min
Service Temperature - +5 Co to +75 Co
Bond Strength ASTM D4541 > 2 N/mm2
Compressive Strength BS 6319-2 70 N/mm2 at 7 days
Experimental Setup Column Preparation
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
After
125 mm
125 mm
750 mm500 mm
Before
R = 25 mm
Experimental Setup Proposed Matrix
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
NC11
N2 N3 U1 U2 U3
NC21 NC22 NC23 UC21 UC22 UC23
N1
NC12 NC13 UC11 UC12
UF13NG11 NG12 NG13 UG11 UG12
UC13
UF23NG21 NG22 NG23 UG21 UG22
N: Standard U: Under
C: CFRP G: GFRP
First Number: # of Wraps Second Number : Sample Number
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results N Group
# P (KN) ∆u ∆y μ∆
N1 937.859 5.258 4.430 1.187
N2 803.907 3.975 3.391 1.172
N3 843.165 4.302 3.348 1.285
Average 861.644 4.512 3.723 1.215
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results NC1 Group
# P (KN) ∆u ∆y μ∆
NC11 917 6.266 4.765 1.315
NC12 1002 4.886 4.143 1.179
NC13 910 5.007 4.090 1.224
Average 943 5.386 4.332 1.240
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results NC2 Group
# P (KN) ∆u ∆y μ∆
NC21 1014 5.701 4.212 1.353
NC22 1010 4.952 4.076 1.215
NC23 1019 5.437 3.956 1.374
Average 1014 5.363 4.081 1.314
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results NG1 Group
# P (KN) ∆u ∆y μ∆
NG11 977 5.639 4.438 1.271
NG12 926 8.147 5.765 1.413
NG13 890 6.650 4.786 1.390
Average 931 6.812 4.996 1.358
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results NG2 Group
# P (KN) ∆u ∆y μ∆
NG21 1044 7.178 3.543 2.026
NG22 1141 7.489 3.139 2.386
NG23 1035 4.656 4.040 1.152
Average 1073 6.441 3.574 1.855
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results U Group
# P (KN) ∆u ∆y μ∆
U1 658 3.084 2.498 1.235
U2 546 4.329 3.407 1.271
U3 742 3.466 3.424 1.012
Average 649 3.626 3.109 1.173
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results UC1 Group
# P (KN) ∆u ∆y μ∆
UC11 871 4.163 3.702 1.125
UC12 912 8.995 6.745 1.334
UC13 893 6.245 5.342 1.169
Average 892 6.468 5.263 1.209
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results UC2 Group
# P (KN) ∆u ∆y μ∆
UC21 1035 7.655 6.706 1.142
UC22 1053 6.629 5.131 1.292
UC23 1035 6.437 5.362 1.200
Average 1041 6.907 5.733 1.211
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results UG1 Group
# P (KN) ∆u ∆y μ∆
UG11 845 5.529 4.890 1.131
UG12 892 6.523 5.023 1.299
UG13 831 7.612 5.826 1.307
Average 856 6.555 5.246 1.245
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results UG2 Group
# P (KN) ∆u ∆y μ∆
UG21 938 5.601 4.446 1.260
UG22 940 9.401 7.598 1.237
UG23 997 6.014 4.478 1.343
Average 959 7.005 5.507 1.280
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results Transverse Strain Gauges
# Transverse # Transverse # Transverse # Transverse # Transverse
N1 -3.47E-04 NC11 - NC21 - NG11 - NG21 -5.40E-05
N2 -3.45E-04 NC12 -2.38E-04 NC22 -5.00E-05 NG12 -3.32E-04 NG22 -6.00E-05
N3 -6.49E-04 NC13 -3.10E-04 NC23 -4.00E-05 NG13 -2.50E-04 NG23 -4.60E-05
Average -4.47E-04 Average -2.74E-04 Average -4.50E-05 Average -2.91E-04 Average -5.33E-05
# Transverse # Transverse # Transverse # Transverse # Transverse
U1 - UC11 -7.40E-04 UC21 -4.19E-04 UG11 - UG21 -3.19E-04
U2 -2.50E-04 UC12 -2.33E-04 UC22 -3.68E-04 UG12 -5.00E-04 UG22 -1.66E-04
U3 -3.10E-04 UC13 -1.90E-04 UC23 -1.00E-04 UG13 -3.00E-04 UG23 -
Average -2.80E-04 Average -3.88E-04 Average -2.96E-04 Average -4.00E-04 Average -2.43E-04
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results Load and Ductility Values# P (KN) ∆u ∆y μ∆
# P (KN) ∆u ∆y μ∆
N1 938 5.258 4.430 1.187 U1 658 3.084 2.498 1.235N2 804 3.975 3.391 1.172 U2 546 4.329 3.407 1.271N3 843 4.302 3.348 1.285 U3 742 3.466 3.424 1.012
Average 862 4.512 3.723 1.215 Average 649 3.626 3.109 1.173NC11 917 6.266 4.765 1.315 UC11 871 4.163 3.702 1.125NC12 1002 4.886 4.143 1.179 UC12 912 8.995 6.745 1.334NC13 910 5.007 4.090 1.224 UC13 893 6.245 5.342 1.169
Average 943 5.386 4.332 1.240 Average 892 6.468 5.263 1.209NC21 1014 5.701 4.212 1.353 UC21 1035 7.655 6.706 1.142NC22 1010 4.952 4.076 1.215 UC22 1053 6.629 5.131 1.292NC23 1019 5.437 3.956 1.374 UC23 1035 6.437 5.362 1.200
Average 1014 5.363 4.081 1.314 Average 1041 6.907 5.733 1.211NG11 977 5.639 4.438 1.271 UG11 845 5.529 4.890 1.131NG12 926 8.147 5.765 1.413 UG12 892 6.523 5.023 1.299NG13 890 6.650 4.786 1.390 UG13 831 7.612 5.826 1.307
Average 931 6.812 4.996 1.358 Average 856 6.555 5.246 1.245NG21 1044 7.178 3.543 2.026 UG21 938 5.601 4.446 1.260NG22 1141 7.489 3.139 2.386 UG22 940 9.401 7.598 1.237NG23 1035 4.656 4.040 1.152 UG23 997 6.014 4.478 1.343
Average 1073 6.441 3.574 1.855 Average 959 7.005 5.507 1.280
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results Comparisons- N Group
Type N NC1 NC2 NG1 NG2
Load (KN) 862 943 1073 931 1014
% Diff - 9.44% 24.56% 8.06% 17.68%
∆u (mm) 4.512 5.386 5.363 6.812 6.441
∆y (mm) 3.723 4.332 4.081 4.438 3.574
μ∆ 1.215 1.240 1.314 1.358 1.855
%Diff - 2.06% 8.15% 11.77% 52.67%
Transverse -4.47E-04 -2.74E-04 -4.50E-05 -2.91E-04 -5.33E-05
%Diff - -38.702% -89.933% -34.899% -88.069%
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results Comparisons- U Group
Type U UC1 UC2 UG1 UG2
Load (KN) 649 892 1041 856 959
% Diff - 37.54% 60.49% 32.02% 47.80%
∆u (mm) 3.626 6.468 6.907 6.555 7.005
∆y (mm) 3.109 5.263 5.733 5.246 5.507
μ∆ 1.173 1.209 1.211 1.245 1.280
%Diff - 3.07% 3.24% 6.14% 9.12%
Transverse -2.80E-04 -3.88E-04 -2.96E-04 -4.00E-04 -2.43E-04
- 38.452% 5.595% 42.857% -13.393%
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results Comparisons- N vs. U Group
Type N UC1 UC2 UG1 UG2
Load (KN) 862 892 1041 856 959
% Diff - 3.52% 20.80% -0.63% 11.25%
∆u (mm) 4.512 6.468 6.907 6.555 7.005
∆y (mm) 3.723 5.263 5.733 5.246 5.507
μ∆ 1.215 1.209 1.211 1.245 1.280
%Diff - -0.49% -0.33% 2.47% 5.35%
Transverse -5.33E-05 -3.88E-04 -2.96E-04 -4.00E-04 -2.43E-04
- 626.88% 454.38% 650.00% 354.69%
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Discussion of Results Mode of Failure
Column Type of Failure Position ColumnType of Failure
Position
NC11 Delamination Top UC11 Delamination Top + MiddleNC12 Delamination Top UC12 Delamination Top + MiddleNC13 Delamination Top UC13 Delamination Top + MiddleNC21 Delamination Top UC21 Delamination TopNC22 Delamination Top UC22 Delamination TopNC23 Debonding Top UC23 Delamination TopNG11 Debonding Middle UG11 Debonding Top + MiddleNG12 Debonding Top UG12 Debonding MiddleNG13 Debonding Middle UG13 Delamination TopNG21 Debonding Top UG21 Delamination TopNG22 Debonding Middle UG22 Debonding Top + MiddleNG23 Debonding Top UG23 Debonding Top
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Conclusion
• The external confinement with CFRP or GFRP materials has increased the load and
ductility of the normal and under designed specimen under axial loading.
• The results of the materials tested showed that CFRP materials has produced the
largest lateral confinement pressure to column specimens. However, GFRP materials
has produced enhancements in ductility.
• Excessive confinement will lead to very sudden and destructive compressive failures,
which must be avoided.
• Externally confined concrete column could undergo large deformation without
complete failure.
IntroductionResearch
Objective & Significance
Literature Review
Experimental Setup
Discussion of Results Conclusion
Special Thanks
• Dr. Adil Al-Tamimi
• Dr. Jamal Abdalla, Dr. Sherif Yehia, and Dr. Bassil Darras
• Eng. Arshi Faridi
• Eng. Ahmed Gadhban
Eng . Assia Lasfer
and thank you for listening …