The document discusses the need for retrofitting of reinforced concrete structures to restore strength and functionality that may have deteriorated due to various factors, including changing loading conditions and environmental impacts. It outlines various retrofitting techniques and materials, particularly focusing on the use of carbon and glass fiber reinforced polymers (CFRP and GFRP) for strengthening beam-column joints. The results demonstrate significant increases in joint strength after retrofitting, showcasing its effectiveness in enhancing structural integrity.

2. Overview
Introduction
a. Need of Retrofitting
b. Retrofitting Techniques
01
Objective of project
Significance of project
Selection of Repair materia0
Essential parameters for repair material
Properties of fibres
Components of fibres
Stress vs. strain curve of FRP
CFRP and GFRP overview
Rates of CFRP and GFRP
Project Planning
Reinforcement Details
Loading Frame Assembly 1,2 and 3
Preparation of Base
Application of Sheets
Mix Design
Performed Activities
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17

3. Introduction
Reinforced concrete is the most commonly used material for the
construction of the structures which are designed in accordance of
the specifications given in the standard codes to meet the service
life.
During the service life if the loading conditions changes due to the
purpose of the structure like beam’s, column and slab this can result
in the non performance of the structure for which it is designed.
The structure are also susceptible to the deterioration due to the
earthquake, flood, cyclone, chloride attack, environmental pollution,
deficiencies of the material used, inadequate design and faulty
construction.
Replacement of the damaged structural element of the existing
particular structure has created the risk of the integrity of the
connecting members.
To restore the required strength of the deteriorated structure,
retrofitting is the only solution.

4. Need of Retrofitting
To restore the required strength of the deteriorated building to the original
strength.
To ensure the safety and security of a building, employees, structure
functionality, machinery and inventory.
To reduce the hazard and losses from the non-structural elements.
Increasing the lateral strength and stiffness of the building.
Increasing the ductility and enhancing the energy dissipation
capacity.
Eliminating sources of weakness or those that produce
concentration of stresses.

5. Retrofitting Techniques
Global
1. Addition of the Shear Wall
2. Addition of Infill
3. Addition of the Steel Bracing
4. Addition of the Wing wall/buttresses
1. Jacketing of the RCC Member
2. Strengthening using Fibre Reinforced
Polymer
3. Jacketing of the beam column joint
4. Strengthening of Individual Footings
Local

6. Strengthening Works
Performance of Specimen
Load Carrying Capacity
Cost Efficiency
Objectives of the Project
Strength and Ductility To increase strength and ductility of specimen.
To use CFRP and GFRP wrapping methods in beam-
column joint for the strengthening works
To find out the performance of specimen wrapped by
CFRP and GFRP towards shear strength
To compare load carrying capacity of CFRP and
GFRP
To compare load carrying capacity of CFRP and
GFRP

7. Shear Strength
Life Span of Structure
Integrity of Joint
Cost Efficiency
Significance of the Project
Serviceability RequirementsTo fulfil the serviceability requirements of the
structure
To increase the shear strength of the RC beam-
column joint
To increase the life span of the structure.
To maintain the integrity of the joint with the frame
member
To identify the efficient fibre reinforced sheets

8.  Selection of the repair material is one of the most important tasks for ensuring
durable and trustworthy repair.
 Though pre-requisite for a sound repair system if detailed investigation and then
determine
the exact cause of the distress, yet an understanding of the process of the
deterioration of the repair materials
 Under the service condition if vital of course availability of the materials of the
relevance, equipment and skilled labor have to be explored before deciding upon
repair.
Selection of the repair material

9. Essential Parameters for the repair material
 The essential parameters for deciding upon a repair material for the concrete are as follows:-
Low Shrinkage Properties
Requisite setting/Hardening properties
Workability
Good bond Strength with existing
Sub strata
Compatible coefficient of Thermal Expansion
Compactible mechanical properties and
strength to that of the sub-strata
No curing required
Alkaline Character
Low air and water permeability
Non- biodegradable

10. Fibre Diameter
(Micro m)
Relative
Density*
Modulus of
Elasticity (GPa)
Tensile
Strength (GPa)
Elongation at
break (%)
Steel 5-500 7.84 200 0.5-2.0 0.5-3.5
Glass 9-15 2.60 70-80 2-4 2-3.5
Asbestos
-Crocidolite 0.02-0.4 3.4 196 3.5 2.0-3.0
-Chrysotile 0.02-0.4 2.6 164 3.1 2.0-3.0
Fibrillated Polypropylene 20-200 0.9 5-77 0.5-0.75 8.0
Aramid (Kevlar) 10 1.45 65-133 3.6 2.1-4.0
Carbon (High Strength) 9 1.90 230 2.6 1
Nylon - 1.1 4 0.9 13.0-15.0
Cellulose - 1.2 10 0.3-0.5 -
Acrylic 18 1.18 14-19.5 0.4-1.0 3
Polyethylene - 0.95 0.3 0.7x10-3 10
Wood Fibre - 1.5 71.0 0.9 -
Sisal 10-50 1.50 - 0.8 3.0

11. Components of Fibre Material
 The choice of fibre frequently controls the properties of composite materials.
 Carbon, Glass, and Aramid are three major types of fibres which are used in construction.
 The most important properties that differ between the fibre types are stiffness and tensile strain.
 Thermosetting resins (thermosets) are almost exclusively used.
 Vinyl ester and epoxy are the most common matrices.
 Epoxy is mostly favored above vinyl ester but is also more costly.
 Epoxy has a pot life around 30 minutes at 20 degree Celsius but can be changed with different
formulations.
 Epoxies have good strength, bond, creep properties and chemical resistance.

12. Stress vs strain curve of various FRP

13. GFRP and CFRP Overview
(Properties of GFRP and CFRP)
Diameter
9-15 micro m
Modulus of Elasticity
70-80Gpa
Relative Density
2.60
Tensile Strength
2-4Gpa
Elongation at Break
2-3.5 %
Diameter
9 micro m
Modulus of Elasticity
230Gpa
Relative Density
1.9
Tensile Strength
2.6Gpa
Elongation at Break
1%
GFRP CFRP

14. CFRP and GFRP Sheet Rates
CFRP
1m X 0.8m
Rate :- Rs900 per runnig m
GFRP
Rate :- Rs350 per kg

15. Project Planning

16. Performed Activities

17. Performed Activities

18. Performed Activities

19. Reinforcement Details

20. Loading Frame Assembly 1

21. Loading Frame Assembly 1

22. Loading Frame Assembly 2

23. Loading Frame Assembly 3

24. Preparation of Base

25. Application of Sheets
 Application of sheet done in two configurations for GFRP and CFRP:-
 L – configuration
 Straight configuration

26. Application of Sheets
 Application of sheet done in two configurations for GFRP and CFRP:-
 L – configuration
 Straight configuration

27. Testing on Control Specimen and its Results

28. Testing on Specimen wrapped by CFRP and
its results

29. Testing on Specimen wrapped by GFRP and
its results

30. Sr No Cement Sand C.A Water
1. For 1m3 (394 Kg) 683.316Kg 1156.176Kg 186lit
2. For 1Kg 1.73Kg 2.93Kg 0.47lit
3. For 50Kg 86.96Kg 146.84Kg 24.5lit
Mix Design

31. Results
Sr No. Specimen Description % increase in the strength of
Joint
1. Strength of the Control Specimen -
2. Strength of specimen wrapped with CFRP in L-configuration 85
3. Strength of specimen wrapped with CFRP in Straight
configuration
57
4. Strength of specimen wrapped with GFRP in L-Configuration 71
5. Strength of specimen wrapped with GFRP in L-Configuration 42

32. Results
Specimen Load at the 1st crack for the Joint (KN)
Base Control 7
L – Shaped Pattern
• CFRP
• GFRP
13
11
Straight Pattern
• CFRP
• GFRP
12
10

33.  No horizontal cracks observed at the level of reinforcement.
 No occurrence of Bond failure.
 For control specimen subjected to the action of the point load, cracks were developed
at the sides and bottom of the specimen.
 While when the specimen wrapped by CFRP and GFRP in L pattern were subjected to
the action of point load cracks were developed at the bottom only and in case of
specimen wrapped in straight pattern, cracks were developed at the sides of the
specimen only.
.
Discussion

34. Load at 1st Crack for Joint
0
2
4
6
8
10
12
14
Control
Specimen
L Shaped
Pattern
GFRP
L Shaped
Pattern
CFRP
Straight
Pattern
GFRP
Straight
Pattern
CFRP
Load at 1st Crack for Joint (KN)
Load at 1st Crack for Joint (KN)

35. Percentage increase in strength of Joints
0
10
20
30
40
50
60
70
80
90
L- Configuration Straight Configuration
CFRP
GFRP

36. Cracks in Control Specimen

37. Cracks in specimen wrapped by CFRP in
straight configuration

38. Cracks in specimen wrapped by GFRP in
straight configuration

39. Cracks in specimen wrapped by GFRP in
L-configuration

40. Cracks in specimen wrapped by CFRP in
L-configuration

41. Conclusion
A total of five beams were cast out of which one was the control specimen and other 4 were
retrofitted with CFRP and GFRP by L and Straight configurations.
No horizontal cracks were observed at the level of the reinforcement, which indicated that there
were no occurrences of bond failure.
Percentage increase in strength of the specimen wrapped with CFRP in straight configuration was
57% while that of the L-configuration was 85%.
Similarly the percentage increase in strength of specimen wrapped with GFRP in straight
configuration was 71% while that of L-configuration was 42%. There was a considerable decrease in
the stiffness of beam after retrofitting due to increased ductile nature

42. Recommendation for further study
Size of the specimen should be small enough so that it can be easily handled.
The bolting connection must be provided to the base plate so as to facilitate easy
removal of the specimen after the testing.
The depth of the footing of the loading assembly to be sufficient enough to prevent
overturning of the specimen.
Proper reconnaissance survey of the loading equipments and its feasibility must
be taken into consideration.

43. Item Quantity of Work
(m3)
Materials
Cement
(Kg)
Sand (Kg) Aggregate
(Kg)
Water (Kg)
RCC Work 0.018 7.092 12.29 20.81 3.348
Footing 0.09 35.46 61.49 104.05 16.74
Cube 0.01012 3.99 6.9 11.73 1.881
Quantity of Material

44. Sr No 7 days curing
(Mpa)
28 days curing
(Mpa)
1 16.80 29.90
2 17.35 30.08
3 16.90 28.66
Compressive strength of Cube

45. Total Expenses

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