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International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 6, June 2017, pp. 687–698, Article ID: IJCIET_08_06_074

Available online at http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=6

ISSN Print: 0976-6308 and ISSN Online: 0976-6316

© IAEME Publication Scopus Indexed

STRENGTHENING OF BEAM-COLUMN

JUNCTION FOR NEGATIVE MOMENT DUE TO

ELIMINATION OF A COLUMN IN THE FRAME

D. Jawaharlal

Research Scholar, Department of Civil Engineering,

Dr. MGR Educational and Research Institute, Chennai – 600 095, India

Prof. Dr. T. Felix Kala

Additional Dean (Engineering & Technology),

Dr. MGR Educational and Research Institute, Chennai – 600 095, India

ABSTRACT

During the life span of a structure, the structural system as a whole or part loses its

design strength and the design intent of the structure becomes unfulfilled. Also due to

the need in the structural configuration under different circumstances such as demand

for vertical expansion, change in use of space, the structure undergoes the process of

retrofitting and rehabilitation. In retrofitting and rehabilitation the structure is altered

in such a way that the revised functional intent is fulfilled and the structure as a whole

is brought to service condition for its designed span of life. Different approaches are

adopted in practice with different techniques and materials. Different structural

member warrants different methods and materials which depend on adoptability,

feasibility, durability. But in the case of beam-column junction, the behaviour is very

complex and the method available is limited. This paper describes and discusses the

different methods followed in practice and suggests few methods in strengthening of

beam-column junction especially in negative moment region in a particular case of

elimination of a column between floor to floor which results in increased moment of

resistance at mid span of column and negative moment region at the column-beam

junction.

Key words: Column-Beam junction, FRP Jacketing, Plate Bonding, Retrofitting,

Strengthening.

Cite this Article: D. Jawaharlal and Prof. Dr. T. Felix Kala, Strengthening of Beam-

Column Junction For Negative Moment Due To Elimination of A Column In The

Frame. International Journal of Civil Engineering and Technology, 8(6), 2017, pp. 687–

698.

http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=6

D. Jawaharlal and Prof. Dr. T. Felix Kala


1. INTRODUCTION

In the life span of a structure, the function of the building for which it has been designed in

original keep changing and the structure is re-configured to suit to the changes by way of

retrofitting the structure by suitable methods which involves addition/ alteration/ removal of

structural elements. But when a column is removed which is primarily an axial load carrying

member which transfers the load on the building to the foundation system. When such a column

is intended to be removed in a floor a comprehensive analysis is required as it involves

strengthening of the whole system of a structural frame which consists of slabs, beams,

columns, and foundations which is a comprehensive and exhaustive analysis. This paper

narrates the different strengthening methods practiced in the field and throws light on

application of new methods which are found to be useful in real time applications to retrofit a

beam-column junction for a particular situation.

2. APPLICATION OF STRUCTURAL STEEL IN STRENGTHENING OF

REINFORCED CEMENT CONCRETE ELEMENTS

The structural steel has been the integral part of any structural system as a whole or part as

composite system. The structural steel has been effectively used to strengthen any structural

members for any incremental strength. The plates are in general used jacket the deficit columns,

the rolled steel sections and compound sections are used to strengthen the flexural members.

Fig.1 shows an opening closed with structural steel frame work. The opening has been created

as a part of structural system, but in later due to change of functional use, the opening had to be

closed with structural steel members. When the change in occupational pattern happens in

multi-story commercial buildings, the change in loading pattern is inevitable. In case of pre-

stressed concrete floor system, strengthening of floor slab is effectively done with the structural

steel truss to cater to the longer span of about 10 to 12 metres as shown in Fig.2.

Figure 1 Structural steel slab system to

close an opening.

Figure 2 Strengthening of pre-stressed slab to

make an opening in the slab for escalator.

Fig.3 shows the structural steel rolled sections are used as edge beam to enable to have

opening to install escalator in commercial premises. The structural steel columns are designed

and placed as temporary supports (Fig.4) to replace the RCC column between two floors. The

replacement of RCC column was carried out due to construction failure. The grade of concrete

has been found to be lesser than the design requirement. The recasting was the only solution as

the other methods will result in increase in the size of the column which would hinder the

functional requirement of the structure.

Strengthening of Beam-Column Junction For Negative Moment Due To Elimination of A Column In

The Frame


3. JACKETING OF STRUCTURAL ELEMENTS

Jacketing of structural elements involves increasing the size of the structural member with

different types of materials. The conventional or high strength concrete is used in general. The

use of high strength concrete reduces the jacketing thickness and a minimum thickness of

100mm is adopted for concrete jacketing. Depends upon the type of material used, the jacketing

is named as reinforced concrete jacketing, steel jacketing, FRP jacketing. The reinforced

concrete jacketing involves placement of new longitudinal reinforcement and transverse

reinforcement bars in the new concrete overlay around existing member. Steel profile jacketing

is done in two ways and the common method is through steel angle profiles placed at each

corner of the existing reinforced concrete member and connected together as a skeleton with

transverse steel straps. In another method of steel jacketing, the concrete member is completely

confined using thin plates. FRP jacketing involves placement of composite material made of

continuous fibres with resin impregnation. The size of FRP jacketing is determined assuming

composite action between fibre and existing concrete. The rupture strength of FRP is used as

its limiting strength and limit state moment capacity of FRP strengthened member is determined

based on the assumption that compressive concrete reaches a strain of 0.0035 and FRP reaches

its maximum strain. Fig.5&6 shows a typical jacketing technique adopted to a column to

increase the axial and moment carrying capacity of column along with strengthening of

foundation system as the columns and foundation need to carry more load due to vertical

development of the building.

Figure 5 Strengthening of foundation and

jacketing of column for additional load on the

column.

Figure 6 Jacketing of column using high

strength concrete.

Out of all methods, the Reinforced concrete jacketing yields better results. The reinforced

concrete jacketing improves flexural strength and ductility. Closely spaced transverse

reinforcement provided in the jacket improves the shear strength and ductility of the concrete

elements.

4. FRP IN STRENGTHENING OF REINFORCED CONCRETE

STRUCTURES

Strengthening of RC beams by using FRPC, One of the most popular techniques for

strengthening of RC beams has involved the use of external epoxy-bonded steel plates and the

flexural strength of a structural member can increase by about 15% with this technique. Steel

bonding technique is simple, cost-effective and efficient. However, it was found that it suffers

from a serious problem of deterioration of bond at the steel and concrete interface due to

corrosion of steel. Other common strengthening technique involves construction of steel jackets

which is quite effective from strength, stiffness and ductility considerations. However, it



increases overall cross-sectional dimensions, leading to increase in self-weight of structures and

is labour intensive. To eliminate these problems, steel plate was replaced by corrosion resistant

and light-weight FRPC plates. FRPCs help to increase strength and ductility without excessive

increase in stiffness. Further, such material could be tailored to meet specific requirements by

adjusting placement of fibres.

Flexural behaviour of RC beams strengthened by FRPC Flexural strengthening of RC

beams using composites can be provided by epoxy bonding of FRPC plate to the portion of

elements in tension, with fibres parallel to the principal stress direction. If fibres are placed

perpendicular to cracks, a large increase in strength and stiffness is achieved compared to

situation where fibres are placed oblique to the cracks. Considerable experimental research has

been conducted for strengthening of RC beams with glass, carbon or Aramid FRPCs to

investigate serviceability, strength enhancement, cracking patterns and failure-modes, etc.

Literature review has shown that nearly 40% strength enhancement is possible for RC beams

strengthened with glass fibre reinforced polymer composite (GFRPC) whereas around 200%

strength enhancement is achieved with carbon fibre polymer composites (CFRPC). In addition

to the fibre type, flexural performance of strengthened RC beams is affected by several factors

such as modulus of elasticity of FRPC and its centre of gravity location relative to the neutral

axis, width of laminate, length of laminate, amount of main and shear reinforcement, number

of FRPC layers, level of loading, FRPC configuration, concrete strength and cover, damage and

loading condition etc.

FRPC material has relatively low modulus of elasticity and linear stress–strain relation up

to rupture with no definite yield point. As a result strengthened beams generally exhibit large

deflection, wide as well as closer cracks and brittle failure mode. Experiments have indicated

catastrophic failure of strengthened beams due to low ductility.

Shear behaviour of RC beams strengthened by FRPC Shear strengthening of RC elements

can be provided by epoxy bonding of FRPC materials with fibres parallel, as practically

possible, to the direction of the shear stresses. In general the shear strength of virgin beam is

increased by 60–120% using FRPC sheets. Fibre orientation may be vertical or perpendicular

to the shear cracks. Shear contribution to the total shear capacity of strengthened RC beams

depends on several parameter including surface preparation, composite fabric shear

reinforcement ratio, amount of main and shear reinforcement, shear span to effective depth

ratio, strength of FRPC, number of FRPC layers, wrapping schemes, depth of sheet across beam

section. U-wrap of sheet provided the most effective strengthening for RC beams with about

119% increase in shear strength. The ultimate resistance of beam cannot be taken into account

by simple superposition of shear capacity contributions because of complex interaction between

concrete, steel and FRPC. This has been reported to be the major obstacle in development of an

analytical formula that can correctly predict the ultimate load of strengthened beams in shear.

Durability of RC beams strengthened by FRPC Seasonal and daily temperature variations

cause freezing and thawing cycles, differential thermal expansion between concrete and FRPC

substrate, resulting in premature plate separation and ultimately failure of strengthened system.

Cross-directional (matrix dominated) properties such as transverse tensile/compressive strength

and in-plane shear were found to be highly affected by environmental effects but fibre was less

sensitive to it.

Bond and development length of FRPC Bond of external FRPC reinforcement to the

concrete substrate is a critical factor for effectiveness of strengthening as delamination of FRPC

laminate from concrete surface can cause failure of concrete structure.

Strengthening of RC columns using FRPC Wrapping of FRPC sheets around concrete

columns is a promising method for structural strengthening and repair. Application of fabric

sheet is quite easy, requiring no specialized tools; thus technique is of practical interest. One of


The Frame


the deficiencies in concrete columns is the lack of lateral confinement and low energy

absorption capacity. External confinement of concrete significantly enhances strength, ductility

and energy absorption capacity of concrete specimens by constructing additional RC cage

around existing columns or using grout-injected steel jackets.

Strengthening of RC beam-columns joint by FRPC Performance of beam-column joints is

very important in determination of the ability of structure to withstand large earthquake and

other lateral loads. Shear failure of beam-column joints has been identified to be the principal

cause for collapse of many moment resisting frame buildings during recent earthquakes. Shear

failure during an earthquake have been attributed to inadequate transverse reinforcements at the

joint and weak-columns/strong-beam design. A study on external beam-column joint has shown

failure of the structure by beam hinging if axial load on the columns is high and beam

reinforcement is less than 1.2%. Several techniques have been applied to strengthen beam-

column joints, including uses of concrete jackets, bolted steel plates. However, it is difficult to

provide effective confinement in the rehabilitation of beam-column joints. Use of FRPC for

strengthening of dilapidated reinforced concrete structures has increased in recent years.

However, behaviour of beam-column connection is complex and still not completely

understood. External FRPC reinforcement is an effective method to increase moment carrying

capacity of beam-column connection by about 60% and shear capacity of the joint by about

35%.

5. THE STATEMENT OF PROBLEM IN STRENGTHENING BEAM-

COLUMN JUNCTION

In case of a continuous beam at the upper most floors, the strengthening of negative moment

region is done as the similar way for positive moment region by applying the methods of

external plate bonding, overlay and/ or external jacketing and so on. In case of intermediate

floors, the suggested technique (Sinaph M. & Namboorimadathil, 2002) is gluing the various

types of fibre reinforced polymer material over the beam and slab near the shear zone as shown

in Fig.7 and in this case restraint caused by the column is not considered. Also in practice,

though the beams are theoretically treated as T-beams, in practice, it is not reinforced as T-

beams. All T-beams are designed and treated as rectangular beams only.

Fig 7 Strengthening of Negative Moment

Region (Sinaph M. Namboorimadathil,

2002)

Fig 8 Suggested Strengthened Scheme for Negative

Moment Region Jumaat M.Z., Rahman M.M. and

Alam M.A (2010)



This way of strengthening with application glue solely depends on the bonding strength

between the laminate and the substrate. In the experiment, the flange width is considered is

arbitrary, but in design and practice the width depends on the span of the slab. Another method

suggested by Jumaat M.Z et al., (2010) is to glue the fibre on all four sides of the column as

shown in Fig.8. In this method also, the parameters such as width of flange, existing

reinforcement in flange, thickness of slab, shear reinforcement are not considered. Also the

applicability of these methods for the edge beam has to be validated.

6. EARLIER RESEARCHES ON STRENGTHENING OF COLUMN-

BEAM JOINTS

Lakshmi.G.A, (2008) has analytically and experimentally studied the behaviour of beam-

column joint under cyclic excitation. The specimen were designed to fail in three different

modes like flexural failure of beam, shear failure of beam and shear failure of columns when

cyclic load is applied. The author has strengthened all the three type of specimen using FRP

materials in such a way that the eventual failure of the system is due to flexural failure of the

beam which is a most acceptable failure mode. The author has obtained the result that the

strengthening of column-beam joint with FRP composite has resulted the transformation of

failure mode of column to the beam and the strength increase has been found to be 45% to 55%

and the analytical study carried by using finite element analysis have in good agreements with

the experimental study.

K.R. Bindhu et al., (2009) have experimented different model specimens of beam column

joints designed for different codal provisions (IS: 456, SP-34 and IS: 13920) and compared the

result and concluded that in all methods of detailing, the joints fail by developing tensile cracks

at the interface between beam and column which satisfies the condition of strong column-weak

beam condition, and the joints had adequate shear resisting capacity and the specimen having

confined reinforcement as per IS: 13920 had an improved energy absorption capacity than the

lateral reinforcement detailing.

Lee W.T et al., (2010) have conducted a study on RCC beam-column joint designed based

on pre-seismic code guidelines which will not have transverse reinforcement strengthened with

CFRP and tested for the structural stiffness, strength and energy dissipation capacity. They have

found the result that the rehabilitation strategy has been effective to increase the ductility of the

joint and transform the failure mode to beam or delay the shear failure mode.

Polies W et al., (2010) have experimented the flat slab column interior joint duly

strengthened with CFRP sheets subjected to monotonic shear and unbalanced moment keeping

the effect of eccentricity as key design parameters. The control specimen was loaded up to

failure and in the strengthened specimen the load has been applied in two stages of 70% of

ultimate load creating flexure cracks in the tension zone and in the second stage of applying

load, the cracked specimen is reinforced using CFRP sheets bonded on the tension cracked

surface. On testing, they have concluded that the CFRP sheets have enhanced and restores the

ultimate loading capacity and stiffness of all cracked specimen and the increment in strength

was in the range of 43% to 51% and also observed that the more the load eccentricity lesser the

strength increment in the rehabilitated specimen.

Kien Le-Trung et al., (2010) have also found from the experimental investigation of 14 no’s

exterior RCC beam column joint specimen strengthened with different configurations of CFRP

sheets that addition of CFRP composites to non-seismic specimen significantly improve the

lateral strength as well as the ductility of the joint. They have adopted different configuration

of wrapping such as T-shape, L-shape, X-shape and strip combinations. Out of the tested

configuration, the X shaped configuration of wrapping was found to be resulted in a better

performance in terms of ductility and strength.


The Frame


K. Balasubramanian et al., (2012) have experimented the performance of beam-column

joint by strengthening in four different ways, by providing CFRP laminates in the top face of

the beam, providing CFRP laminates in the top face of the beam and confining the junction

with CFRP sheets, providing MS flat section in the top face of the beam, anchored with MS

bolts on both faces and by providing additional reinforcement in the top face by cutting a groove

and filling the groove with non-shrink cementitious material and confining the joint with CFRP

sheets. They have aimed at getting equal flexural strength for both upward and downward

loading. For analytical predictions the model suggested by Ibarra et al. (2005) was applied, and

the performances of the specimen were evaluated under cyclic loading. To predict the failure

the hysteresis model of deformation vs. the total cumulative energy dissipation was used and in

experiment it was found that having equal initial stiffness in all specimen, the yield load taken

corresponding to a deflection of 5mm has varied, the specimen strengthened only providing

CFRP laminates on the top face of the beam has taken comparatively 25% lesser load (32 Kilo

newton against 39 KN) than the other specimen. The authors have concluded that the

strengthening by confining the junction with mild steel flat on top faces of the beam with MS

bolts including additional reinforcement has resulted well in cyclic reversal loading.

H.Y. Choi & J.Y. Lee (2012) have tested the strength of beam-column joints as per the

design guidelines recommended by the three countries (America, Japan and New Zealand).

They have conducted the experiments by designing the joints both by arch and truss mechanism

and by both incorporating the features of both the arch and truss mechanism and derived a new

equation and concluded that the new equation could be used to evaluate the strength and

ductility of the joint and also recommends that this new equation will take care of the bond

strength of the joint and observed that the co-efficient of variance is 20 to 25% with the, ACI

and AIJ guidelines.

Arul Gnanapragasam et al., (2016) have investigated the effectiveness of strengthening

beam-column joints using natural and artificial fibres. They have used basalt fibres as

monolithic composite (BFRP) and as hybrid composite along with glass fibres. They have tested

6 specimen, 2 no’s control specimen, 2 no’s monolithic basalt fibre and 2 no’s with hybrid

wrapping. The investigation was for the initial and ultimate cracking loads, energy absorption,

deflection ductility and stiffness at ultimate. The authors have found that for hybrid composites,

an increase of 125% in initial cracking load, 60% increase in ultimate load, 208% increase in

energy absorption, 131% increase in deflection ductility and for monolithic basalt fibre

polymer, 100% increase in initial cracking load, 20% increase in ultimate load, 71% increase

in energy absorption, 43% increase in deflection ductility were obtained. Also they have

observed that the stiffness has reduced by 24% when hybrid composite were used. One

important behaviour of joint observed by them was the control specimen failed by crushing of

column whereas the strengthened specimen failed in peeling of the FRP composites in the beam

which indicates the strengthened joint show the strong column-weak beam concept.

Upon review, it is observed that the experimental studies are conducted about 77% on

models, 1% on prototypes, 20% is analytical and 2% on review of different studies. Majority

of the studies are on beams and flexural behaviour is analysed at most with carbon fibre

reinforced polymer composite being the predominant material used for strengthening. As far as

the methods of strengthening concerned, the external addition dominates than any other method.

Pre-stressing and Near Surface Mounted technique has significant technological values but

researches done are comparatively little.



7. LIMITATIONS IN THE CURRENT PRACTICES

While strengthening the beams or any structural elements using FRP composites, it has been

proven that it has given an increase in strength but the % of increase varies from 15% to 70%

which depends on authors arbitrary selection of parameters like width of wrap, length of wrap,

size of substrate, available reinforcement, size of specimen considered for testing, grade of

concrete, grade of reinforcement steel used in the structural member,

But in reality, the results obtained from the laboratory experiment will vary based on

parameters like exposure condition, life of the structure, residual life of the structure, the strain

already undergone, actual loading condition, workmanship in implementing the strengthening

scheme, probable difference prototype and model, aspect ratio. Especially the practical errors

are not taken care in laboratory researches especially in using FRP composites, the reliability

of performance of FRP composite solely depends on gluing properly. Even in laboratory

condition, the de-bonding failure is the primary failure encountered. So, a straight approach or

model on strengthening scheme on structural members on real scenario varies from case to case.

In general the FRP composites are selected arbitrarily and experimented and the findings

are analysed. It is observed that there is no need based study done to strengthen the structural

element to the required level of strengthens at negative moment region.

8. PROPOSED METHOD OF ANALYSIS AND DESIGN FOR

STRENGTHENING

In the layout of columns as shown in Fig. 9, two numbers of columns have to be removed due

to functional change in the structure and additional requirement of one more floor involving

strengthening of the adjacent columns, footings, and beams for both the sagging and hogging

moments. Strengthening of columns and foundations could easily be designed using the method

of jacketing with design guidelines of various codal provisions. For strengthening of beam two

structural models are created using the Staadpro software, one with the column in position and

the other with the columns removed. The difference in moment is arrived through static analysis

the beam is designed for negative moment at the column-beam junction and for the positive

moment at mid-span, two methods are suggested one is jacketing of beam with reinforced

cement concrete with additional reinforcement and the another with compound structural steel

rolled sections externally supported/ bonded to the soffit of the beam through the anchor

fasteners.

Figure 9 Column layout of a frame


The Frame


The column-beam junction under discussion is beam no.47& 48 in the frame as shown in

figure 4&5. From the structural analysis the forces in the beam are extracted and are tabulated

in Table 1&2.

Figure 10 Original configuration of the frame Figure 11 Revised/ Proposed configuration of

the frame

Table 1 Beam End Forces In The Pre-Revised Structural Configuration

Beam

No Node Loading

Axial

(Fx)

Shear

(Fy)

Shear

(Fz)

Torsion

(Mx)

Bending

(My)

Bending

(Mz)

47 71 1.50

(DL+LL) 1.71 61.12 -0.04 0.74 0.02 31.03

70 -1.71 54.04 0.04 -0.74 0.10 -21.51

48 69 0.91 44.31 0.34 -0.45 -0.39 14.68

70 -0.91 55.89 -0.34 0.45 -0.42 -28.64

Table 2 Beam End Forces In The Revised Structural Configuration.

Beam

No Node Loading

Axial

(Fx)

Shear

(Fy)

Shear

(Fz)

Torsion

(Mx)

Bending

(My)

Bending

(Mz)

47 71 1.50

(DL+LL) -21.13 164.56 0.23 5.12 -0.34 161.37

70 21.13 -48.88 -0.23 -5.12 -0.29 125.70

48 69 -21.08 168.07 -0.26 -2.03 0.39 157.60

70 21.08 -67.40 0.26 2.03 0.25 126.15

The composite beam element is designed for the difference in forces arrived from the

analysis through the software and with the aid of design manual SP: 16. The two types of

strengthening schemes are designed and suggested as per figure 12 & 13.



Figure 12 External Strengthening Using Structural Steel Rolled Sections.

Figure 13 Beam Jacketing Using Reinforced Concrete

9. CONCLUSIONS

This paper analyzed and suggested methods which are feasible for practical applications in the

retrofitting of concrete structures demanding changes in the structural configuration which are

increasing nowadays.

The main advantages of using these methods are mainly practical in the field applications

and the design method is conventional and can be applied in all scenarios.

This increases the durability of the structure as a whole as the strengthening design and its

application is integrated with the existing system and in compliance with the properties and

behavior of substrate materials.


The Frame


In the earlier research works, the design approaches have been application of various

techniques and materials to strengthen the structural elements and finding out the incremental

strength in the member. But in practice, the strength requirement is the driving factor.

The parameters like existing design strength, available reinforcement, change in curtailment

pattern (upon removal of an existing intermediate column), stiffness variation at the beam-beam

junction, increase in span, available head room, architectural requirement, were considered in

the field practice and the design approach is chosen accordingly.

The limitation of this method is in case of requirement of higher thickness of member at the

negative moment region and it will not be feasible in the internal column-beam junction as the

floor level has to be maintained at level.

10. RECOMMENDATIONS

A finite element analysis and subsequent experimental study shall be conducted using the

proven FRP composite materials to strengthen the all the three prime structural elements

(foundations, columns, beams).

The technology of Pre-stressing may be tried out to strengthen the negative moment region

which is gaining popular in strengthening the machine foundations, circular or rectangular

tanks.

Research on composite use of structural steel for positive moment and rebar along with

grouting or with near surface mounted fibre reinforced polymer strips for negative moment

region may be experimented.

Also, the effect of reaction from upper column at the junction need to be analyzed and there

has been no scientific or empirical model has been established involving all relevant parameters

like thickness or external strengthening materials, length to be glued, various modulus of

material, exposure, property of substrate, existing strength of substrate, strain already attained,

existing stress, etc.

REFERENCES

[1] IS: 456-2000, “Code of practice for reinforced concrete design”, New Delhi: Bureau of

Indian Standards, 2000.

[2] IS: 800-2007, “General construction in steel – Code of Practice”, New Delhi: Bureau of


[3] SP-16, “Design aids for reinforced concrete to IS: 456-1978”, New Delhi: Bureau of Indian

Standard, 2007.

[4] SP: 6 (6), “Hand book for structural engineers – Application of plastic theory in design of

steel structures”, New Delhi: Bureau of Indian standards, 1995.

[5] IS: 15988-2013, Seismic evaluation and strengthening of existing reinforced concrete

buildings – guidelines”, New Delhi: Bureau of Indian Standards, 2013.

[6] IS: 14687-1990, “False work for concrete structures – Guidelines”, New Delhi: Bureau of


[7] IS 4000-1990, “High strength bolts in steel structures – Code of Practice”, New Delhi:

Bureau of Indian Standards, 1990.

[8] ACI Committee 440 2R-02, “Guide for the design and construction of externally bonded

FRP systems for strengthening of concrete structures” American Concrete Institute, USA,

2010.

[9] A. Arul Gnanapragasam, G. Chitra, and S. Robert Ravi, “Study on Strengthening of RC

Beam Column Joint Using Hybrid FRP composites”, Scientific Research Publishing, Vol:

pp: 2846-2856, 2016.



[10] K. Balasubramanian, N. Lakshmanan, C. Antony Jeyasehar, G. Ramesh and B.H.

Bharatkumar, “Evaluation of Performance of Retrofitted Reinforced Concrete Beam

column Joints – A simplified model”, Asian journal of Civil engineering (building and

housing), Vol.13, No. 6, 2012.

[11] K.R. Bindhu, P.M.Sukumar, and K.P. Jaya, “Performance of Exterior Beam-column joints

under seismic type loading”, ISET journal of earthquake technology, Paper no 503, Vol. 46,

No. 2, June 2009. Pp. 47-64.

[12] Kien Le-Trung, Kihak Lee, Jaehong Lee, Do Hyung Lee and Sungwoo Woo (2010),

“Experimental study of RC beam–column joints strengthened using CFRP composites”,

Composites: Part B 41, pp 76-85.

[13] Lakshmi.G.A. (2008), “Numerical studies of strengthening of beam-column joint under

cycle excitation using FRP laminates”, Journal of structural engg, Vol.35, No.1, pp 59-65.

[14] Lee W.T., Chiou Y.J. and Shih M.H. (2010), “Reinforced concrete beam–column joint

strengthened with carbon fiber reinforced polymer”, Composite Structures 92, pp 48–60.

[15] Polies W, Faouzi G, Khaled S (2010), “Rehabilitation of interior reinforced concrete slab-

column connections using CFRP sheets”, Construction and Building Materials. 24: 1272-

85.

[16] Chen, J.F. H.Y. Choi and J.Y. Lee, “Strength Evaluation of Reinforced Concrete Beam-

Column Joints”, 15th World Conference on Earthquake Engineering, 2012. Structural

Engineering, ASCE, 129(5), 615-625.

[17] Sinaph M. Namboorimadathil, J. Gustavo Tumialan, and Antonio Nanni, “Behaviour of RC

T-Beams strengthened in the negative moment region with CFRP Laminates”, Quakewrap,

2002.

[18] Jumaat M.Z., Rahman M.M. and Alam M.A., "Flexural strengthening of RC continuous T

beam using CFRP laminate: A review". International Journal of the Physical Sciences.

2010; 5(6): 619-625.

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