seismic rehabilitati on of rcc beam column · pdf filebeam-column joint with corbel tested...

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International Journal of Civil Engineering and Technology (IJCIET)Volume 8, Issue 4, April 2017, pp.

Available online at http://www.iaeme.com/IJCIET/issues.

ISSN Print: 0976-6308 and ISSN Online: 0976

© IAEME Publication

SEISMIC REHABILITATI

School of Mechanical and

Asst. Professor, School of Mechanical and Building Science

ABSTRACT

Beam-Column joints are critical regions in reinforced con

which are most vulnerable or sensitive to seismic forces. Hence strengthening and

rehabilitant beam-column joint is imperative to save the structure and its inhabitants

in case of earthquake forces. Numerous and large scale retrofit

reinforced polymer (FRP) composites are being undertaken worldwide. This

experimental study aims to investigate the effectiveness of strengthening beam

joints using synthetic fibres. In this study, Aramid fiber (synthetic fibr

strengthening and rehabilitant of beam

and tested under monotonic loading with the help of universal testing machine. At the

end, test results of control and rehabilitated samples were compared t

experimental conclusions in all tested specimens will embolden future investigations

in same direction for long term performance to enhancing this AFRP in structural

applications.

Key words: Reinforced Concrete, Compressive Strength, Flexural

tensile Strength, Beam-Column Joints, Aramid Fibre Reinforced Polymer, Monotonic

Loading, Rehabilitant of specimens.

Cite this Article: Jimmy Gupta and Dr. A. Arun Kumar Seismic Rehabilitation of

RCC Beam-Column Joint,

8(4), 2017, pp. 2173-2186.

http://www.iaeme.com/IJCIET/issues.

IJCIET/index.asp 2173 [email protected]

International Journal of Civil Engineering and Technology (IJCIET) 2017, pp. 2173–2186 Article ID: IJCIET_08_04_246

http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=4

6308 and ISSN Online: 0976-6316

Scopus Indexed

SEISMIC REHABILITATION OF RCC BEAM

COLUMN JOINT

Jimmy Gupta

M.Tech Student,

School of Mechanical and Building Science

VIT University, Chennai Campus

Chennai, India.

Dr. A. Arun Kumar

School of Mechanical and Building Science, VIT Univer

Chennai Campus Chennai, India.

Column joints are critical regions in reinforced concrete or RCC structures


column joint is imperative to save the structure and its inhabitants

in case of earthquake forces. Numerous and large scale retrofitting works using fibre


experimental study aims to investigate the effectiveness of strengthening beam

joints using synthetic fibres. In this study, Aramid fiber (synthetic fibres) was used for

strengthening and rehabilitant of beam-column joints. Many specimens were prepared


end, test results of control and rehabilitated samples were compared t



Reinforced Concrete, Compressive Strength, Flexural Strength, Split

Column Joints, Aramid Fibre Reinforced Polymer, Monotonic

Loading, Rehabilitant of specimens.

Jimmy Gupta and Dr. A. Arun Kumar Seismic Rehabilitation of

International Journal of Civil Engineering and Technology

http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=4

[email protected]

asp?JType=IJCIET&VType=8&IType=4

ON OF RCC BEAM-

VIT University,

crete or RCC structures


column joint is imperative to save the structure and its inhabitants

ting works using fibre


experimental study aims to investigate the effectiveness of strengthening beam-column

es) was used for

column joints. Many specimens were prepared


end, test results of control and rehabilitated samples were compared together. The



Strength, Split

Column Joints, Aramid Fibre Reinforced Polymer, Monotonic

Jimmy Gupta and Dr. A. Arun Kumar Seismic Rehabilitation of

Journal of Civil Engineering and Technology,

asp?JType=IJCIET&VType=8&IType=4

Seismic Rehabilitation of RCC Beam-Column Joint

http://www.iaeme.com/IJCIET/index.asp 2174 [email protected]

1. INTRODUCTION AND LITERATURE REVIEW

Almost everybody knows about concrete and also heard that it is a thing which is used in

construction of different structures like multi-stories buildings, Flyovers, bridges etc, where

concrete is nothing but a combination of binding material, fine aggregates and course

aggregates with proper percentage of water. Reinforced cement concrete (RCC) is a versatile

material, popularly used worldwide in most of the structures. How-ever, its performance

during the earthquakes or seismic forces has created lot of questions in the mind of

researchers. Earthquake may cause reinforced concrete structures to collapse, loss of leaving

lives and staggering economic losses also. Most of the structures in India are not able to resist

even moderate seismic or earthquake loading. Under seismic activity, it is imperative for RC

structures to have lateral resistance capacity against brittle breakdown. Non-earthquake

resistant buildings which designed by using non-seismic code of practice are vulnerable to

seismic excitations. Since reconstructing and demolishing RC buildings are expensive,

retrofitting the limited fraction of structural components and building can offer a workable

solution for ensuring the safety of structure and people. So, now are going to study it.

The Beam-Column Joint is the crucial as well as critical zone in a reinforced concrete

moment resisting frame as shown in fig-I. It is subjected to large forces during seismic

activity or severe ground shaking and its performance has a significant influence on the

response of the building. The functional requirement of a joint, which is the zone of

intersection of beams and columns, is to enable the adjoining members to develop and sustain

their ultimate capacity. The joints should have adequate strength and stiffness to resist the

internal forces induced by the framing members but lot of buildings are there in India which

are non-earthquake or seismic resistant. These type of weak buildings create large casualties

of leaving lives during moderate or heavy natural ground shaking. So, we used here aramid

fiber reinforced polymer (AFRP) to overcome this major loss.

Fiber Reinforced Polymer (FRP) is a popular material which normally used in

retrofitting or strengthening reinforced concrete structural elements in recent years. It is a

composite material made of a polymer matrix reinforced with natural or artificial fibres.

Some fibres are like carbon, aramid, glass, basalt and many more such as paper, wood,

asbestos or natural fibers have been also used. As above said, aramid fibers are used in this

experimental investigation which is a type of synthetic fiber.

Aramid fibers are the superstar family in fiber world which are a class of heat-resistant

and strong synthetic fiber. The name of fiber comes from a combination of two words,

“Aromatic Polyamide”. These fibers have excellent attributes such as good resistance to

abrasion, no melting point, low flammability, non-conductive, sensitive to ultraviolet

radiations as well as acids and salts etc.

Due to their superior strength-to-weight ratio and heat-resistant properties, aramid fibers

can be used in retrofitting of structural components to improve their strength against seismic

activities. Here, these fibers are used in retrofitting or rehabilitation of beam-column joint

which is a crucial zone in structure.

Jimmy Gupta and Dr. A. Arun Kumar


Figure 1 Beam-Column Joint

Beam-column joints, being the vertical and lateral load resisting members in reinforced

concrete (RC) structures are particularly vulnerable to breakdown during seismic activity [1].

It has also been initiated that exterior beam column joints are more accessible than interior

joints [2]. This may be attributed to inadequate strength to tolerate the lateral loads by the

joints with the reason being destitute detailing without due consideration to earthquake

provisions. This complication results in reduced ductility with diagonal shear developed in

the joints leading to catastrophic rapture. Insufficient transverse reinforcement in the joints

and weak column—strong beam design are the prime reasons observed for the joint shear

breakdown during seismic action [3]. Beam-column Joints must be formed to allow for the

dissipation of huge amount of energy in to the neighbouring aspects without significant

damage of strength and ductility [4]. If the column or vertical member is not wide enough or

if the stability of concrete in the joint is low, there is inadequate bond of concrete on the steel

bars. In such type of circumstances, the bar slips inside the joint, and beams lose their load

carrying capacity [5]. FRP materials have number of agreeable characteristics such as

extreme high strength, immunity to corrosion, ease of installation, availability in convenient

tailor made forms etc [6]. GFRP jacketing comes out to be an impressive technique to

recapture the stiffness and strength of damaged joints [7]. GFRP jackets were found to be

capable of boosting the shear resistance of the joints by enhancing ductility of it. By using

this jacketing, the integrity of the concrete might be managed by confinement, significantly

improving the ductility and the load carrying capacity of the rehabilitated zone [8]. Web

bonded FRP type retrofitting at joints was found to result in 40% increment in the lateral load

resisting capacity of reinforced concrete frames [9].

2. SCOPE & OBJECTIVE

The intention of this investigation is to study the seismic retrofitting or rehabilitation of

beam-column joint with corbel tested under monotonic loading using AFRP (Aramid Fiber

Reinforced Polymer) so that structures which constructed without consideration of seismic

code and can’t be able to resist seismic forces, can be retrofit and rehabilitate easily in future

because reconstructing and demolishing the RC buildings are too expensive.

3. RETROFITTING AND STRENGTHEN OF BEAM-COLUMN JOINT

The strengthening and retrofitting of beam-column joint take place using AFRP (Aramid

Fiber Reinforced Polymer). The beginning step of strengthening and retrofitting the beam-

column joint is to repair and close the gaps of cracks as shown in fig-II. It is to ensure that

cracks should be perfectly repaired prior to retesting of specimen under monotonic or cyclic

load and diagonal cracks at top area of the column were repaired with epoxy coating to cover

up structural cracks. The wrapping of AFRP sheets on prime coat epoxy resin (Araldite GY



257 and Hardener HY 840) takes place once the epoxy injection grouting dried. The column

is retrofitted with three different layers of AFRP sheets from all sides of it and the transverse

beam near the joint region was also retrofitted using three different layers of AFRP sheets on

both side of the joint as shown in fig III. After the cracks were treated, specimens kept for

required period of curing so that FRP could be set properly and made a perfect bond with

concrete.

Figure 2 Retrofitting Technique

Figure 3 Bonding of concrete with AFRP sheet

4. BONDING PROCEDURE

Before wrapping the AFRP sheets, the surface and edges of the specimens were ground by

mechanical means and surface of concrete was slightly chiseled off with pointed chisel to

remove the surface material for enhancing good bonding and cleaned with fresh water to

abolish all dirt and debris. Once the surface of specimen had been prepared, the epoxy resin

was prepared. Mixing was carried out in the proportion of 1:0.5 with Araldite GY 257 and

Hardener HY 840. The epoxy coating was enforced on the specimen and the 1st layer of

AFRP sheets was placed over the surface of beam-column joint as shown in fig-III. A hand

roller was also used to roll over the surface gently to abolish the voids. After 7 days of curing

period, the epoxy coating was enforced over the sheet and then, the second layer of fiber

sheet was placed, similarly third layer of sheet was applied.

5. EXPERIMENTAL WORK

5.1. Materials And Their Properties

Some common material are used in this research work which must to prepare concrete such

as ordinary Portland cement (OPC) of 53 grade, different size of aggregates, highly water

reducer type Super Plasticizer which has 1.425 specific gravity, fresh water and aramid fiber

reinforced polymer (AFRP) sheet. Aramid type FRP sheet is a non-degradable substance

which has no melting point and has good resistance to abrasion.

Cement: In this experimental examination Ordinary Portland cement (OPC) of 53-grade

is used. So, the attributes of cement as per IS code 12269:1989 are as follows:



Table 1 Properties of Cement

Property Average value of OPC used in

this investigation

Standard value

Specific Gravity 3.14 ----

Consistency (%) 32 ----

Initial setting time (min.) 74 >30

Final setting time (min.) 240 <600

Soundness 2.9 <10

Fineness 98.50 ----

Aggregates: Maximum Strength of concrete is depends on attributes and behavior of

aggregates such as shape of aggregates, particle size distribution inside wetness etc. Chemical

reaction between dust free aggregates and cement paste creates bond or strength between

them. So can say, aggregates are the major factor by which concrete gains its strength.

The different important attributes of aggregates were determined as per IS code

2386:1963 as shown in table II.

• Coarse aggregates: Coarse aggregates were use in this research work which was 20mm

as well as 12.5mm size with free from dust and aggregates were crushed angular shape

type.

• Fine aggregates: Fine aggregates were use of less than 4.75mm size which means, are

passing through 4.75mm sieve. It helps to fill voids in concrete mixture and assist in

producing uniformity and workability.

Table 2 Properties of Aggregates

Property Fine Aggregates Coarse

Aggregates

Specific gravity 2.63 2.74

Water

absorption

0.67 0.95

Size of

Aggregates

(mm)

< 4.75 < 20

Bulking of

Sand (%)

28 ----

Sieve Analysis Zone III-

confirming to IS

383:1970

----

5.2. Preparation of Specimens

In this experimental work, IS code 10262:2009 used for prepare M30 concrete mix by using

OPC- 53 grade cement, fine aggregates which passed through 4.75mm sieve, dust free coarse

aggregates of two different sizes (20mm and 12.5mm) of crushed angular shape, BASF types

super-plasticizer or highly water reducer chemical, fresh water and with 0.42 standard water

cement ratio. Standard dosage of super-plasticizer (0.6% of cement by weight) was used in

this mix to maintain concrete workability. This concrete mix was moulded in form of

standard 100mm x 100mm x 100mm size of cube mould, 100mm x 100mm x 500mm size of

prisms, 100mm x 200mm size of cylinders and exterior beam-column where column size was



100mm x 100mm with height 1000mm and beams size was 100mm x 100mm with length

750mm as shown in fig-IV.

Figure 4 Preparation and Curing of Specimens

Details of the Specimen

The dimensions and reinforcement detail of the beam-column joint used in present study are

shown in figure, and beam-columns are as follows:

Design Load of Joint = 10 kN

Req. Area of Steel = 157.7 mm2

Prov. Area of steel = 226.08 mm2

Beam

Cross section = 100mm x 100mm with length 750mm.

Top Reinforcement = Two bars of 8mm diameter.

Bottom Reinforcement = Two bars of 10mm diameter and one bar

of 8mm diameter.

Stirrups = 6mm diameter with the spacing of 75mm

centre to centre (c/c).

Column

Cross section = 100mm x 100mm with length 1000mm.

Main Reinforcement = Four bars of 8mm diameter.

Vertical Ties = 6mm diameter with the spacing of 75mm

centre to centre (c/c).



Table 3 Concrete Mix Proportions

Concrete Mix Properties for 1 Cubic Meter

Materials Mass of Materials

(kg/m³)

W/C = 0.42

Cement 333

Fine Aggregates 750

Coarse

Aggregates

20 mm 790

12.5 mm 484

Super-Plasticizer 2.0

Water 140

Required quantities of given materials were mixed with accurate proportion in drum type

mixing machine with proper batching. Batching is nothing but a process of measuring

materials so that, can mix with each other in require quantity which is given in table III.

Highly water reducer type super-plasticizer was also added in concrete in require percentage,

firstly it mixed in water and then that mixture was added steadily in mixture machine.

Figure 5 Compression Test on Cubical Sample

Mixing was continued till uniform mixing of raw material, could be achieved. Once the raw

materials were mixed completely, mixture was placed in bigger pan and then it poured in

cube shaped moulds, prisms and cylinders for compressive strength test, flexural strength test

and split tensile strength respectively and also in T-shaped moulds and vibrated it properly for

sufficient time so as not to have any voids. Inside portion of moulds were coated with oil

before pouring concrete so that samples could be remove easily from moulds after 24 hours.

Moulds were filled with mixture in three different layers and each layer was tamped 25 times

with the help of steel tamping rod. After 24-hours, when mixture settled thoroughly in

moulds, de-moulded it and cured with wet sacks for recommended time period.

5.3. Testing of Specimens

In this experimental examination, compression, flexural and spilit tensile test used for

determine compressive, flexural and tensile strength of specimens after 7-day and 28-day of

curing time. These tests were used firstly for conventional (normal cement-concrete)

specimens and after that for FRP specimens so that it can be possible to compare

conventional values and FRP values together. Testing of beam-column joint is also done by

universal testing machine to find its load carrying capacity or strength by applied monotonic

loading. So, discussion about tests is as follows:

Compression Test: This is most frequent test conducted on hardened concrete by

compression testing machine of 2000 KN capacity as shown in fig-V. By this test it can be



judge that whether concreting has been done properly or not. It is so easy to perform and

carried out only on that specimen those are cubical in shape, which has only two types 150 x

150 x 150mm and 100 x 100 x 100mm. In this study, 100 x 100 x 100 mm size of cubes used

to determine compressive strength.

Flexural Test: Direct measurement of tensile strength of PCC specimens is not possible so

flexural strength test is used to determine tensile strength of PCC. It is measure of PCC

prisms to resist failure under bending. It is expressed as Modulus of Rupture (MR) in Mega-

Pascal’s (Mpa) and determined by standard test methods of ASTM C 78 (third-point loading)

or ASTM C 293 (centre-point loading). Flexural strength of concrete samples should be about

10 to 20 percent of compressive strength of that sample which depends on size, type and

volume of aggregates used. The modulus of rupture (MR) determined by ASTM C 293 or

centre-point loading is always greater than modulus of rupture (MR) determined by ASTM C

78 or third-point loading. But in this study, ASTM C 293 or centre-point loading method was

used to determine flexural strength of concrete by used 500 x 100 x 100mm size of concrete

samples as shown in fig-VI.

Split Tensile Test: The split tensile strength of concrete was tested on cylindrical specimens

by compression testing machine by kept specimen in horizontal position as shown in figure

VI. Cylindrical specimens of size 100mm x 200mm were prepared for testing after curing

period of 28-days.

Figure 6 Testing on different specimens

Beam-Column Joint Test: The testing arrangement of beam-column joint is shown in tested

which is in fig-VI, with a constant axial load on the column and a static load at the beam tip.

Beam-column joint was tested by hydraulic jacks under initial axial restraining force of 10kN

to the column. The monotonic load test was conducted on the control and retrofitted

specimens of reinforced concrete joint. If the column axial load applied by the hydraulic

jacks, exceeded by one-half of its capacity, the effect of axial load will be more on the joint.

So as to maintain the seismic load or earthquake load behavior on beam-column joint, the

axial load was controlled and it is decided to apply the load up to one-half of its load carrying

capacity only. Where, Hydraulic jack was used to apply axial load and it was monitored by



the data acquisition and load cell system. Total of four specimens were casted and prepared

for testing, including two control specimens, which were tested beyond its ultimate failure

strength and remaining two were tested by applying seventy percentage of their ultimate load.

After testing, the failed control specimens were repaired by fill the crack portions with

cement paste after cleaning the surfaces of sample by sand paper. Same grade of concrete was

used in damaged portion and compact it well. The rehabilitated specimens were placed in

fresh water for 28 days of curing and after curing samples wrapped with AFRP sheet in

different layers. Remaining two specimens were also wrapped by using aramid fibre

monolithically after giving 70 percentage of ultimate load.

6. COMPARISON OF TEST RESULTS AND DISCUSSION

From the light of the experimental investigation work, behavior of beam-column joints found

for control and Strengthened beams after 28-days testing, behavior of cubical samples, prisms

and cylindrical samples are discussed in following lines which are as-

Compressive strength of cubical samples after required period of wet curing when compared

control with AFRP samples found that it increased more than 2%. This test conducted on

2000kN capacity of compression testing machine under compression load as per IS 516:1959

as shown in fig. V and similar values of compressive strength results are given in table IV.

The results came from compression test are in form of maximum load carried by cubical

sample before it fail.

The compressive stress or strength (N/mm2) can be determined by dividing the maximum

load carried by cubical samples to its cross-sectional area.

Therefore,

� = �

� N/mm

2

Where,

P = Maximum load carried by cubical sample before failure,

A = Cross-sectional area cube which is nothing but 100mm x 100mm

= 10000 mm2,

σ = Maximum Compressive Stress (N/mm2)

Flexural strength of prisms after required period of wet curing when compared control with

AFRP samples found that it increased more than 24%. This test conducted on 2000kN

capacity of flexural testing machine under centre point loading as shown in fig. VI and

similar results are given in table V. The results came from flexural strength test are in form of

maximum load carried by beam under centre-point loading before it fail under bending

compression. By using the fundamental bending equation, can determine the bending stresses.

We know that,

Where,

M = Moment of Resistance which is nothing but load in to perpendicular distance (Nmm),

I = Moment of Inertia about neutral axis which is bd³/12 (mm4),

σb = Bending Stress (N/mm2),

y = Extreme fibre distance from neutral axis which is nothing but d/2,



b = Width of Beam (mm), d = Depth of Beam (mm).

Tensile strength on cylindrical samples after required period of wet curing when compared

control with AFRP samples found that it increased more than 5%. This test conducted on

2000kN capacity of compression testing machine under axis load as shown in fig. VI and

similar values of tensile strength results are given in table V. The results came from split

tensile test are in form of maximum load carried by cylindrical samples before it fail. By

using the fundamental mathematical equation, can determine the tensile stresses which is

2��

Where,

P = Maximum load carried by cylindrical sample before failure,

D = Diameter of Sample in (mm),

L = Length of sample in (mm).

Testing on beam-column joint conducted on universal testing machine under monotonic or

cyclic loading as shown in fig-VI, from which a new relation of beam column strength is

found which is failure comes on column first in control testing but in AFRP sample failure

comes first on beam so this is a important result of this test ‘strong column weak beam’, it

will help to prevent fall down the whole structure. Many parameters were found as given in

table VI and VII, such as stiffness which is nothing but ratio of ultimate load to the maximum

displacement, measured in kN/mm and similar results where it increased by more than 30%,

are shown in table VII and AFRP sheet helped to reduce deflection of member.

Table 4 Compressive Strength Results

S. No. Mix

Density of

concrete

(kg/m3)

Avg. Comp. Stress

(N/mm2)

1-Day 7-Day 28-

Day

1. Control 2473 17.53 33.00 43.89

2. AFRP 2458 24.13 36.33 44.76

Table 5 Flexural and Tensile Strength Results

Flexural Strength

S. No. Mix Density of

Concrete

(kg/m3)

Avg. Bending

Stress

(N/mm2)

7-Day 28-Day

1. Control 2467 4.957 6.473

2. AFRP 2453 6.244 8.010

Tensile Strength

1. Control 2390 3.0 3.89

2. AFRP 2425 3.36 4.10

http://www.iaeme.com/IJCIET/index.

Chart 1

Chart 2

Chart 3

Chart 4

0

10

20

30

40

50

Co

mp

. S

tren

gth

0

2

4

6

8

10

Fle

xu

ral

Str

eng

th

0

1

2

3

4

5

Ten

sile

Str

ength

0

2

4

6

8

10

12

14

16

Lo

ad

(k

N)


IJCIET/index.asp 2183 [email protected]

Chart 1 Compressive Strength of Specimens

Chart 2 Flexural Strength of Specimens

Chart 3 Split Tensile Strength of Specimens

Chart 4 Initial & Max. Ultimate Load of Specimens

Control AFRP

Different Specimens

1-Day

7-Days

28-Days

Control AFRP

Different Specimens

1-Day

7-Days

28-Days

Control AFRP

Different Specimens

1-Day

7-Days

28-Days

C 1 C 2 A 1 A 2 R 1 R2

Specimens Details

Initial

Cracking load

Ultimate Load

[email protected]



Table 6 Values of Initial and Ultimate Cracking Load for Different Specimens

Specimens

Type

Specimen Detail Initial Cracking

Load

(kN)

Max. Ultimate

Load (MUL)

(kN)

Yield

Load (kN)

Control C1 5.5 10.5 5.0

C2 6.0 11.0 5.2

AFRP A1 7.5 14.5 6.8

A2 7.0 13.5 6.2

Rehabilitated R1 6.4 12.0 5.7

R2 6.2 12.6 5.4

Table 7 Values of Deflection-Ductility Ratios and Stiffness

Specimen

Types

Specimen Details Deflection

(mm)

Deflection-Ductility

Ratios (DDR)

Stiffness

(kN/mm)

Control C1 11.0 2.20 0.950

C2 13.5 2.59 0.810

AFRP A1 8.0 1.17 1.820

A2 9.5 1.53 1.421

Rehabilitated R1 10.1 1.77 1.188

R2 10.6 1.96 1.200

Chart 5 Relation of Max Ultimate Load & Max Deflection

Chart 6 Relation of MUL & Deflection-Ductility Ratio

0

2

4

6

8

10

12

14

16

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Lo

ad

(k

N)

Deflection (mm)

C 1

C 2

A 1

A 2

R 1

R 2

0

2

4

6

8

10

12

14

16

0 1 2 3 4

Lo

ad

(k

N)

Deflection-Ductility Ratio (DDR)

C1

C2

A1

A2

R1

R2



7. CONCLUSION

Based on experimental investigation the following conclusions can be drawn;

• Mechanical properties such as compressive strength, flexural strength and tensile strength

were also found better with AFRP sheet when it compared with control by 2%, 24% and

5% respectively.

• The above experimentally findings showing, AFRP found to be more efficient for the

treatment of exterior beam-column joint. By retrofitting the joint with AFRP sheet, the

lateral strength is increased by 14% and the initial cracking strength was found to be

increased by 9% when it compared with control specimens.

• The stiffness of joint also increases by more than 35% and found decrement in maximum

deflection value by 15% after rehabilitating when it compared with control specimen

results.

• This type of fibrous material can be beneficial for concrete to convert it brittle to ductile

manner as shown in chart-6 of deflection-ductility ratio. This unique property conversion

is found by compare the deflection-ductility ratio of control and AFRP specimens.

• In the control specimen, the failure comes in the column but in the retrofitted specimen

failure comes in the beam so from this, the strong column weak beam concept is achieved

and it helps to prevent the failure of entire structure.

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