# Introduction n the last few decades, moderate and severe earthquakes have struck different places in the world, causing severe damage to reinforced concrete (RC) structures. Retrofitting of existing structures are the major challenges that modern civil engineering field is facing these days. Recent evaluation of civil engineering structures has demonstrated that most of them will need major repairs in the near future. Up gradation to higher seismic zones of several cities and towns in the country has also necessitated in evolving new retrofitting strategies. In RC buildings, portions of columns that are common to beams at their intersections are called beam-column joints. Since their constituent materials have limited strengths, the joints have limited force carrying capacity. When forces larger than these are applied during earthquakes, joints are severely damaged. Beam column joints in a reinforced concrete moment resisting frames are crucial zones for transfer of loads effectively between the connecting elements (i.e. beams and columns) in the structure. In normal design practice for gravity loads, the design check for joints is not critical and hence is not usually done. But, the failure of reinforced concrete frames during many earthquakes has demonstrated heavy distress due to shear in the joints that culminated in the collapse of the structure. # a) Objectives In general this investigation was carried out to study the behaviour of the beam-column joint under static and reverse loading. In more specific terms this research was conducted to achieve the following objectives ? Studies and behaviour of reinforced concrete beamcolumn joint retrofitted with Basalt fibre reinforced polymer sheets (BFRP). the volumetric fraction of the fibers on the fracture toughness of geopolymeric cement concretes reinforced with basalt fibers. ? T. Cziga´ny(2006) 2 The strength properties of hybrid composites improved owing to surface treatment and this was proven by mechanical tests and microscopic analysis, as well. ? Jongsung Sim,(2006) 3 et al This study investigates the applicability of the basalt fiber as a strengthening material for structural concrete members through various experimental works for durability, mechanical properties, and flexural strengthening. ? M.M. Smadi et al(2008) 4 Ten slab-column connections were tested under combinations of gravity and lateral loads to investigate the effect of adding steel fibers to concrete mix on the structural behavior of normal-and high-strength slab-column connections. ? Bu¨ lent O¨ ztu¨ rk (2006) 5 et al In the present study, hybrid friction materials were manufactured using ceramic and basalt fibers. Ceramic fiber content was kept constant at 10 vol% and basalt fiber content was changed between Experiments show that fiber content has a significant influence on the mechanical and tribological properties of the composites. ? Xin Wang et al (2010) 6 To overcome the limitations of conventional steel stay cables in a thousandmeter scale cable-stayed bridge, hybrid basalt and carbon (B/C) FRP cables were investigated to achieve integrated high performances in the bridge of this scale as a replacement for steel cables. ? Mohamed F.M. et al (2010) 7 Commonly used fiberreinforced polymer (FRP) includes Carbon, Glass, and Aramid FRP composites. The aim of the study is twofold. In case of different types of FRP composites, providing equivalent confinement modulus (lateral stiffness), five models are employed to find the FRP-confined concrete stressstrain relationship of three scale-model circular columns. ? Catherine Papanicolaou , et al (2010) 8 Externally bonded grids are used in this study as a means of increasing the load-carrying and deformation capacity of unreinforced masonry (URM) walls subjected to cyclic loading. # c) Experimental Investigation The experimental program consisted of testing of nine reinforced concrete beam-column joint specimens. The columns had a cross section of 200 mm x 200 mm with an overall length of 1500 mm and the beams had a cross section of 200 mm x 200 mm with a cantilevered portion of length 600 mm. In fhree specimens, the lateral ties in the column are provided with spacing 180 mm c/c as per IS 456:2000. In remaining three specimens, the lateral ties in the column are provided with spacing 80 mm c/c and 100 mm c/c as per IS 13920:1993. The concrete mix was designed for a target strength of 30 MPa at the age of 28 days. The load carrying capacity of the column was evaluated as 525 kN as per the code IS 456-2000. ii. Casting of Test Specimen # d) Parameters Investigated The Reinforced concrete beam column joint specimens were cast using specially fabricated steel moulds. Two moulds were prepared for this purpose. The sides of the mould were removed after 24 hours from time of casting and the test specimens were cured for water using gunny bag coverings. 3 cubes of sizes 150 x 150 x 150 mm were cast along with each test specimen for evaluating the 28day compressive strength of concrete. The fabricated reinforcement steel was placed inside the mould and it is kept in position using cover blocks. Concrete was mixed manually and poured into the moulds. Care was taken to see that the concrete was properly placed and compacted beneath and also on the sides of the mould using a needle vibrator. iii. Preparation of the Retrofitted Specimens The failed specimens BCJ 1, BCJ 2, and BCJ 3, were retrofitted and new specimens BCJR1, BCJR2 and BCJR3. The concrete near the area of failure was removed completely. After applying cement paste in this area, the portion was filled and compacted with the same grade of concrete. The specimens were cured for 28 days. Before wrapping the Basalt fiber sheet the faces of the specimens were ground mechanically to remove any laitance. All the voids were filled with putty. Then a two component primer system was applied on the concrete surface and allowed to cure for 24 hours. A two component epoxy coating was then applied on the primer coated surface and the Basalt fiber sheet was immediately wrapped over the entire surface of the reinforced concrete beam-column joint. A roller was then applied gently over the wrap so that good adhesion was achieved between the concrete surface and the Basalt fiber wrap, as suggested by the manufacturers and allowed to cure for seven days. Another coat of the two component epoxy was applied over the fiber sheet. Then the second wrap was applied by following the same procedure and allowed to cure for a further period of seven days. Both the wrapped layers were orthogonal to each other. # iv. Description of the Test Program The RC beam-column joint specimens were tested using loading frame in the structural laboratory of Karunya University. A push-pull jack was set up in the structural laboratory. Both the column ends were provided with hinged boundary conditions. At one of the column ends the axial load was applied by using hydraulic jack of 500 kN capacity which has a load measuring arrangement fitted to it. A transverse load was applied at the free end of the beam by using a push pull jack. A deflectometer was placed on the other side of the beam which shows the deflection that occurs at the point of application of load on the beam. The testing involves pushing of the beam using the push pull jack by applying the load in the pushing direction up to control deflection of 75mm. Then the pulling load was applied until the beam comes back to its original position. So, one cycle of load reversal was applied to the test specimens. i.e. the beam was pushed from the normal position, then pulled to the normal position, then it was pulled back from the normal position and again pushed back towards the normal position. The deflectometer readings were noted down at particular load intervals and the deflection of the beam was determined. Typical view of test setup is shown in figure . II. While pulling more cracks occurred at compression side of beam and it propagated into column. Cracks widened and spalling of concrete also observed. # Discusson of Test Results BCJ 2 : This specimen has been designed and detailed as per code IS 456:2000. An axial load of 30 % of the safe load on column was applied. The value of the axial load applied was 180 kN. The lateral load applied on the beam was at an interval of 5KN. First crack appeared on the tension side of the beam at a load of 20.9KN. Further three to four cracks developed on the tension side were observed. At a load 25.9KN first crack developed on the compression side of the beam and further cracks were widen on both compression and tension side of beam. At a load of 41.7KN crack on the tension side started propagating into the column. Spalling of concrete were also started on the compression side of the beam. The application of load was stopped when the controlled deflection of 70.5mm. the load corresponding to that deflection was 52.6KN. While pulling more cracks occurred at compression side of beam and it propagated into column. Cracks widened and spalling of concrete also observed. BCJ 3 : This specimen has been designed and detailed as per code IS 456:2000. An axial load of 45% of the safe load on column was applied. The value of the axial load applied was 270KN. The lateral load applied on the beam was at an interval of 5KN. First crack appeared on the tension side of the beam at a load of 17.6KN. Further three to four cracks developed on the tension side were observed. At a load of 21.7KN first crack developed on the compression side of the beam and further cracks were widen on both compression and tension side of beam. At a load of 35.2KN crack on the tension side started propagating into the column. Spalling of concrete were also started on the compression side of the beam. The application of load was stopped when the controlled deflection of 70.50 mm. the load corresponding to that deflection was 44.6KN While pulling more cracks occurred at compression side of beam and it propagated into column. Cracks widened and spalling of concrete also observed. BCJ 4 : This specimen has been designed and detailed as per code IS 13920:1993. An axial load of 15% of the safe load on column was applied. The value of the axial load applied was 90 kN. The lateral load applied on the beam was at an interval of 5KN. First crack appeared on the tension side of the beam at a load of 21.9KN. Further three to four cracks developed on the tension side were observed. At a load of 27KN first crack developed on the compression side of the beam and further cracks were widen on both compression and tension side of beam. At a load of 43.6KN crack on the tension side started propagating into the column. Spalling of concrete were also started on the compression side of the beam. The application of load was stopped when the controlled deflection of 70.5mm. the load corresponding to that deflection was 55KN. While pulling more cracks occurred at compression side of beam and it propagated into column. Cracks widened and spalling of concrete also observed. : This specimen has been designed and detailed as per code IS 13920:1993. An axial load of 30% of the safe load on column was applied. The value of the axial load applied was 180KN. The lateral load applied on the beam was at an interval of 5KN. First crack appeared on the tension side of the beam at a load of 24KN. Further three to four cracks developed on the tension side were observed. At a load of 29.8KN first crack developed on the compression side of the beam and further cracks were widen on both compression and tension side of beam. At a load of 48.2KN crack on the tension side started propagating into the column. Spalling of concrete were also started on the compression side of the beam. The application of load was stopped when the controlled deflection of 70.5mm the load corresponding to that deflection was 61KN. While pulling more cracks occurred at compression side of beam and it propagated into column. Cracks widened and spalling of concrete also observed. BCJ 6 : This specimen has been designed and detailed as per code IS 13920:1993. An axial load of 45% of the safe load on column was applied. The value of the axial load applied was 270KN. The lateral load applied on the beam was at an interval of 5KN. First crack appeared on the tension side of the beam at a load of 20.2KN. Further three to four cracks developed on the tension side were observed. At a load of 25KN first crack developed on the compression side of the beam and further cracks were widen on both compression and tension side of beam. At a load of 40.5KN crack on the tension side started propagating into the column. Spalling of concrete were also started on the compression side of the beam. The application of load was stopped when the controlled deflection of 70.5mm. the load corresponding to that deflection was 51.3KN. While pulling more cracks occurred at compression side of beam and it propagated into column. Cracks widened and spalling of concrete also observed. # b) Results of the Experimental Investigation on Retrofitted Specimens BCJ R1 : This specimen has been retrofitted with Basalt FRP sheets. An axial load of 15% of the safe load on column was applied. The value of the axial load applied was 90KN. The lateral load applied on the beam was at an interval of 5KN. First crack appeared on the tension side of the beam at a load of 23.8KN. Further three to four cracks developed on the tension side were observed. At a load of 29.4KN first crack developed on the compression side of the beam and further cracks were widen on both compression and tension side of beam. At a load of 47.6KN crack on the tension side started propagating into the column. Spalling of concrete were also started on the compression side of the beam. The application of load was stopped when the controlled deflection of 70.5mm. the load corresponding to that deflection was 59.8KN. While pulling more cracks occurred at compression side of beam and it propagated into column. Cracks widened and spalling of concrete also observed. BCJ R2 : This specimen has been retrofitted with Basalt FRP sheets. An axial load of 30% of the safe load on column was applied. The value of the axial load applied was 180KN. The lateral load applied on the beam was at an interval of 5KN. First crack appeared on the tension side of the beam at a load of 26.1KN. Further three to four cracks developed on the tension side were observed. At a load of 32.4KN first crack developed on the compression side of the beam and further cracks were widen on both compression and tension side of beam. At a load of 52.4KN crack on the tension side started propagating into the column. Spalling of concrete were also started on the compression side of the beam. The application of load was stopped when the controlled deflection of 70.5mm. the load corresponding to that deflection was 66.3KN. While pulling more cracks occurred at compression side of beam and it propagated into column. Cracks widened and spalling of concrete also observed. BCJ R3 : This specimen has been retrofitted with Basalt sheets. An axial load of 45% of the safe load on column was applied. The value of the axial load applied was 270KN. The lateral load applied on the beam was at an interval of 5KN. First crack appeared on the tension side of the beam at a load of 22KN. Further three to four cracks developed on the tension side were observed. At a load of 27.1KN first crack developed on the compression side of the beam and further cracks were widen on both compression and tension side of beam. At a load of 44KN crack on the tension side started propagating into the column. Spalling of concrete were also started on the compression side of the beam. The application of load was stopped when the controlled deflection of 70.5mm. the load corresponding to that deflection was 55.3KN. While pulling more cracks occurred at compression side of beam and it propagated into column. Cracks widened and spalling of concrete also observed. Conclusions ? In the case of specimens having reinforcement details as per code IS 456:2000, there is an increase of 14.4% in load carrying capacity and 18.87% in energy absorption capacity, when the axial load on column was increased from 15% to 30%. ? In the case of specimens having reinforcement details as per code IS 456:2000, there is an increase of 12.90% in load carrying capacity and 16.61% in energy absorption capacity, when the axial load on column was increased from 15% to 45%. ? In the case of specimens having reinforcement details as per code IS 13920:1993, there is an increase of 16.71% in load carrying capacity and 21.06% in energy absorption capacity, when the axial load on column was increased from 15% to 30%. ? In the case of specimens having reinforcement details as per code IS 13920:1993, there is an increase of 12.25% in load carrying capacity and 14.10% in energy absorption capacity, when the axial load on column was increased from 15% to 45%. # Global Journal of Researches in Engineering # Global Journal of Researches in ![b) Literature Review Dylmar Penteado Dias (2005) 1 et al The purpose of this work was to investigate the influence of I Journals Inc. (US)](image-2.png "") ![Details of Beam Column Joint Specimen i. Preparation of Mould Moulds made of steel sheet had been welded and prepared for casting the beam column joint specimen. It consists of a long steel plate and two Lshaped welded plates and this assembly was bolted together by using square plates at the ends. The inner dimensions of the mould are 1500 x 200x 200 mm in the column portion and 600 x 200 x 200 mm in the beam portion.](image-3.png "") ![Figure describes the above mentioned casting and curing operations.](image-4.png "") ![a) Results of the Experimental Investigation onControlled Specimens BCJ 1 : This specimen has been designed and detailed as per code IS 456:2000. An axial load of 15 % of the safe load on column was applied. The value of the axial load applied was 90KN. The lateral load applied on the beam was at an interval of 5KN. First crack appeared on the tension side of the beam at a load of 19KN.Further three to four cracks developed on the tension side were observed. At a load of 23.5KN first crack developed on the compression side of the beam and further cracks were widen on both compression and tension side of beam. At a load of 38.1KN crack on the tension side started propagating into the column. Spalling of concrete was also started on the compression side of the beam. The application of load was stopped when the controlled deflection of 70.5mm. the load corresponding to that deflection was 47.8KN.Global Journal of Researches in EngineeringXIII Issue v v](image-5.png "") ![Studies on Behaviour of Rcc Beam-Column Joint Retrofitted with Basalt Fiber Reinforced Polymer Sheet Axial Load on Column (Controlled and Retrofitted Specimens) III. Finite element Analysis u sing Ansys a) Solid 65 (3D Reinforced Concrete Solid) and 45 (3D Structural Solid) SOLID 65 elements were used to model reinforced concrete problems or reinforced composite materials (FRP). This element has eight nodes each node having three translational degrees of freedom in the nodal X, Y & Z directions as shown in Figure 5.5. The Solid 65 may be used to analyse cracking in tension and crushing in compression and solid 45 element has stress stiffening, large deflection, placticity, large strain capabilities, creep etc. The element may be used to analyse cracking in tension and crushing in compressionUp to three rebar specifications may be defined. The typical solid 65 element was shown in fig. Solad 65 Element LINK 8 Link 8 Is A Spar Element, Which May Be Used In Variety Of Engineering Applications. Depending Upon The Applications, The Element May Be Thought As A Truss Element, Cable Element, Reinforcing Bar And Bolt. The Three-Dimensional Spar Element Is Having Two Nodes And Each Node Having Three Translational Degrees Of Freedom. This Element Is Capable Of Plasticity, Creep, Swelling And Stress Stiffening Effects. of Loads and Boundary Condition Displacement boundary conditions are needed to constrain the model to get a unique solution. To ensure that the model acts the same way as the experimental beam, boundary conditions need to be applied at points of symmetry, and where the supports and loadings exist. Both ends of the column were provided hinged boundary condition. A lateral load was applied at the free end of the beam. The load applied in model which had detail as per code IS 456:2000 was 23 kN. Similarly in model which had details as per code 13920:1993 ,the load applied was 26 kN. The comparative result were given in table.](image-6.png "") ![Displacement Solution For Beam-Column Joints As Per Code IS 13920:1993 For The Load of 61.5 kN Displacement Solution For Beam-Column Joints As Per Code IS 456 Retrofitted Specimen 66.9 kN IV.](image-7.png "") ![](image-8.png "") ? In the case of specimens retrofitted by Basalt FRPwrapping, there is an increase of 14.58% in loadcarrying capacity and 16.31% in energy absorptioncapacity, when the axial load was increased by15% to 45%.? In the case of specimens having reinforcementdetails as per code IS 13920:1993 with 15% of axialloading on the column, there was an increase of18.5% in load carrying capacity and 19.5% increasein energy absorption capacity than the specimensYear 2013with reinforcement details as per code IS 456:2000 with same axial load on column. ? Year 2013VolumeVolumeD D D D )D D D D )((? In the case of specimens retrofitted by Basalt FRPwrapping, there is an increase of 31.89% in loadcarrying capacity and 33.07% in energy absorptioncapacity, when the axial load on column wasincreased from 15% to 30%. © 2013 Global Journals Inc. (US) © 2013 Global Journals Inc. (US) Studies on Behaviour of Rcc Beam-Column Joint Retrofitted with Basalt Fiber Reinforced Polymer Sheet © 2013 Global Journals Inc. (US) Studies on Behaviour of Rcc Beam-Column Joint Retrofitted with Basalt Fiber Reinforced Polymer Sheet © 2013 Global Journals Inc. (US)BCJ 5Studies on Behaviour of Rcc Beam-Column Joint Retrofitted with Basalt Fiber Reinforced Polymer Sheet © 2013 Global Journals Inc. (US) © 2013 Global Journals Inc. (US) © 2013 Global Journals Inc. (US) Studies on Behaviour of Rcc Beam-Column Joint Retrofitted with Basalt Fiber Reinforced Polymer Sheet Displacement Solution For Beam-Column Joints As Per Code Is 456: * Shear Strengthening of beam column joints Dylmar Penteado Dias 2005 ELSEVIER Engineering Structures 1 * Special manufacturing and characteristics of basalt fibre reinforced hybrid polypropylence composites: Mechanical properties and acoustic emission study TCzigany Science Direct Composites Science and Technology 66 2006 Elsevier * Effectiveness Of CFRP Jackets And RC Jackets In Post Earthquake And Pre Earthquake Retrofitting Of Beam Column Sub Assemblages JongsungSim Journal of engineering structures 006) 3 * Performance Of Nonseismically Designed RC Beam Column Joints Strengthen By Various Schemes Subjected To Seismic Loads GAppa Roa MMahajan MGangaram Journal of structural engineering 4 2008 * The transfer length in reinforced concrete structures strengthened with composite plates: Experimental study and modellind Bu¨ Rk Science Direct Composites Science and Technology 5 2006 Elsevier * Behaviour of Concrete Beam Column Connection reinforcement with hybrid FRP sheet XinWang Science Direct Engineering Structures 57 6 2010 Elsevier * Effectiveness of CFRP-jackets and RC-jackets in post-earthquake and preearthquake retrofitting of beam-column sub assemblages FMMohamed Science Direct Engineering Structures 30 7 2010 Elsevier * Effectiveness of CFRPjackets and RC-jackets in post-earthquake and preearthquake retrofitting of beam-column sub assemblages CatherinePapanicolaou Science Direct Engineering Structures 30 8 2010 Elsevier * Post-Yield Stiffnesses and residual deformation of RC bridge Column reinforced with ordinary rebars and steel fibre composite bars FMMohamed ZhishenFahmy GangWu Wu Science Direct Engineering Structures 32 2010 Elsevier * Experimental Investigation on Influence of Development Length in References Références Referencias Retrofitting Reinforced Concrete Beam Column Joints SRobertRavi GPrinceArulraj NBMCW 2009 4 * Experimental Investication on Beam-Column Joints for Bulent Ozturk,Fazli Arslan,Sultan ozturk SRobertAnoop GPrinceRavi Arulraj Science Direct Tribology International 40 2007 Elsevier Hot wear properties of ceramic and basalt fibre reinforced hybrid friction materials * CziganyTibor JansonVad PoloskeiKornel " Basalt Fiber As A Reinfored Of Polymer Composites" Periodica Polyte-ChnicaSer MECh. ENG 49 1 2005 * Retrofitting of RCC Column-to-Beam Connections Ze-JunGeng Composites Science and Technology 58 1998 ELSEVIER * Lateral Load Response Of High Performance Fibre Reinforced Concrete Beam Column Joints M JamalShannag NabeelaAbu-Dyya Journal of construction and building materials 19 2005 * Design Of RC Beam Column Joints Under Seismic Loading -A Review DevadosMenon PradipSarkar RajeshAgrawal Journal of structural engineering 33 2007 * Global Journal of Researches in Engineering