Reinforced Beam Column Joints Research Articles

EFFCT OF HOOPS AND COLUMN AXIAL LOAD ON SHEAR STRENGTH OF HIGH-STRENGTH FIBER REINFORCED BEAM-COLUMN JOINTS

A reinforced concrete frame is referred as "RIGID FRAMES". However, researches indicate that the Beam-Column joint (BCJ) is definitely not rigid. In addition, extensive research shows that failure may occur at the joint instead of in the beam or the column. Joint failure is known to be a catastrophic type which is difficult to repair. This study was carried out to investigate the effect of hoops and column axial load on the shear strength of high-strength fiber reinforced Beam-Column Joints by using a numerical model based on finite element method using computer program ANSYS (Version 11.0). The variables are: diameter of hoops and magnitude of column axial load. The theoretical results obtained from ANSYS program are in a good agreement with previous experimental results.

Thermal Analysis of Reinforced Beam-Column Joint

In concrete structures, temperature changes can cause strains of the same order of magnitude as live and dead loads in some circumstances. When thermal expansion or contraction is controlled, thermal stresses are induced. This report discusses the performance of reinforced joints under thermal loading conditions. Here we analysed the variance in stress and deflection when the temperature increases. The joints are modelled in ETABS and imported into ANSYS for further thermal analysis. The aim is to evaluate the RC beam-column joints at high temperatures in transient response. The results discuss how RC joints respond to temperature variations. The deformations with temperature variation are examined at high-temperature conditions.

Numerical Study On Response Of Exterior Beam-Column Joint Under Cyclic Loading

In Present scenario, recent earthquakes have illustrated the severity of existing reinforced concrete (RC) beam-column joints to lateral loading. The sub-assemblage of Beam-Column are severe portion in reinforced concrete moment resisting frame as the high shear forces and larger moments getting attracted towards the joint. The Philosophy of Exterior beam-column joint are to observe its behaviour and has a significant role on the response of the reinforced concrete structure. This study includes numerical study on Exterior reinforced beam column joint with adequate shear reinforcement at joint as per IS: 13920-2016 and without shear reinforcement at joint as per IS: 456-2000. The seismic performance of G+5 RC Building of Zone III analyzed using SAP2000 and output of maximum shear force and bending moments are obtained, and one of the exterior beam-column joints at an intermediate storey is designed and satisfied for strong column and weak beam concept. The earthquake analysis of RC building of Zone III are carried out by incorporating all the modifications as per IS 1893:2002(Part-I) for Seismic loading, the loading is followed as per IS: 875 for dead and live loads and design as per code IS 13920:2016 and IS456:2000. Full scaled specimens were Numerically modelled in ANSYS 19.0 for constant axial load on column top and cyclic loading on beam end of each specimen, detailed as per IS 456:2000 and the other as per IS 13920:2016, were tested and response are obtained. This study outlined that model of IS13920:2016 performs more effective in controlling the seismic responses compared with model of IS456:2000. Further, there is significant reduction in Shear stress and observed improved ductility by providing adequate shear reinforcement in joint core of beam-column sub-assemblage.

Seismic Analysis of Basalt Fiber Reinforced Beam Column Joint under Cyclic Loading

Abstract: Beam-column joint assemblage in the RC moment-resisting framed structures is a critical seismic element because its behaviour under severe earthquake motions has a significant effect on failure mode , strength and deformation of the building structures. Basalt Fiber Reinforced Concrete (BFRC) is a concrete with short , discrete lengths of basalt fiber that randomly dispersed. Structures under seismic zone five are often badly damaged or can collapse during earthquakes. The observations from recent earthquakes show that many RC structures have failed in the brittle behaviour of beam-column connections due to the deficiency of seismic details in the joint regions. In this study, RC beam column specimen are modelled in the Ansys with excitation of cyclic loading. Attempts are made to study the performance of the test specimen by studying loop hysteresis, stiffness behaviour and energy dissipation. From the results it has shown that basalt fiber reinforced beam column joint produces less deformation and it act as crack arresters also it produces increase in joint core stiffness compared to conventional concrete beam column joint

Comparative Study on the Behaviour of Steel Reinforced Beam-Column Joint with GFRP Bars

Beam-column joints are the crucial zones in the moment resisting structure and are designed to achieve the desired strength and durability. In extreme weathering conditions, the steel in the reinforced concrete is more susceptible to corrosion. So, the steel should be provided with the precautionary measure like coating, etc, if used in such conditions. This results in the use of Fibre Reinforced Polymer (FRP) bars as an alternative to steel since it is non-corrodible. Several researches were done by using FRP bars as an alternative to steel. It is identified that the flexural strength of the beam reinforced with FRP bars were reduced compared to the beams with steel bars. To increase the flexural strength, the fibres were added to the beam. And the seismic behaviour of the beam-column joint will be studied. In this study, a journal proposed by Mohammed Hasaballa and Ehab El-Salakawy is validated using FEA Software package and the results were compared. The comparison between these results was proposed. The failure study is undertaken and compared with GFRP and Steel.

Adaptive Autoregressive Modelling Based Structural Health Monitoring of RC Beam-Column Joint Subjected to Shock Loading

In the present work, a novel technique based on the combination of singular spectral analysis (SSA) and recursive estimate of coefficients of adaptive autoregressive (AR) modelling is employed to identify the damage in the reinforced (RC) beam-column joints. The damage is induced by imparting shock load at the tip of the beam-column joints. The damage is identified with the help of the acceleration response of the healthy and damaged specimens excited by high intensity white noise. The proposed approach has two major components, first, filtering and removing the noise from the dynamic response using the singular spectral analysis and second, modelling the filtered response using adaptive AR process to get the recursive estimate of coefficient matrix for baseline and damage states. The coefficients evaluated for each time instant are presented in a multi-dimensional subspace to form distinct clusters corresponding to a healthy and damaged state. In order to identify and quantify the damage, the geometrical and statistical measures are evaluated that quantifies the segregation of clusters. In total, three distinct measures are used to quantify the damage, namely, Euclidean distance (ED), Mahalanobis distance (MD) and Bhattacharyya distance (BD). The BD accounts the variation in the distribution of both the clusters, thereby shows superior results comparatively than ED and MD. The results of DSFs also manifest the superiority of BD over the other two DSFs. These geometrical and statistical distances are the damage sensitive feature (DSF) to identify and quantify the damage in the specimen due to the shock load. The obtained results of all the DSFs show good consistency with the maximum deformation of the specimen due to shock loading highlighting the accuracy of the proposed algorithm.

A Study on Behavior of Headed Bars Made of Fiber-Reinforced Polymers in Rcc Exterior Beam Column Joints

Seismic pressures on a reinforced concrete moment-resisting structure are known to create critical and essential regions at the reinforced beam-column joints. Beam-column junctions are a microcosm of the whole structure, therefore brittle behavior at these points predicts brittle action. Ductile behavior at beam-column joints predicts ductile action. Under the influence of seismic forces, the joints between RC beams and columns are exposed to high shear stresses. Learn more about the performance of fiber-reinforced polymer headed bars in rcc external beam column joints in this publication.

Development of finite element model for embedded carbon fiber–reinforced polymer rod in reinforced concrete frame joints

The stiffness and strength of joints are the main factors in providing stability and ductility of a structure during dynamic load such as earthquake. In the high-humidity areas, the reinforcement is exposed to corrosion, which commonly occurs in the joints, due to the presence of micro-cracks in the joints, shrinkage or other concrete casting issues. Therefore, one of the main failure mechanisms of building during an earthquake is caused by damage in the joints in humid areas. This is mainly caused by corroded steel reinforcement, which reduces functionality of the frame joints in transferring the loads. This study proposes a new design for reinforced beam–column joints with embedded carbon fiber–reinforced polymer rods, which possesses extremely high strength and resistance against corrosion and high stiffness. The finite element model for embedded carbon fiber–reinforced polymer in the joints was developed in order to evaluate the performance of the proposed joints during earthquake execution. The developed program was verified through an experimental test on reinforced concrete frame subjected to vibration using dynamic actuator. The finite element program was implemented for one-story reinforced concrete frame and two-story frame building with proposed joints and seismic analysis. The results demonstrated a significant improvement in the performance of the frames reinforced with embedded carbon fiber–reinforced polymer in joints in terms of lateral load resistance capacity and failure mechanism.

Plastic hinge relocation in exterior reinforced beam–column joint and compliance issues to seismic design guidelines—A review

AbstractThe current recommendations for the design of monolithic reinforced concrete beam–column joints allowed for the provision of transverse reinforcements at the joint to avoid brittle shear failure of the joint during seismic events but neglected the effect of plastic hinge penetration in the joint leading to bond deterioration and shear failure, especially for external frames. In this paper, previous studies conducted by different authors using the seismic design recommendations are reviewed for failure modes and the effectiveness of the code recommendations to avoid joint failure. Various retrofitting strategies to upgrade nonseismically designed beam–column joints are also reviewed. Methods of plastic hinge relocation in beam–column joints of new construction were proposed and verified with numerical simulation. This study contributes to knowledge by highlighting areas of concern in current design guidelines and a call for further research on code compliant exterior beam–column joint for better seismic performance.

Experimental investigation on the structural performance of a reinforced cold-formed steel beam–column joint

A reinforced beam–column joint specific to mid-rise cold-formed steel (CFS) dwellings was proposed and studied by six full-scale cyclic loading tests. Afterwards, a moment–rotation relationship prediction model and a numerical model of the joint were established. The results show that: (i) the joint has a certain bending moment transmission capacity; (ii) the joint’s moment–rotation curve has distinctive three-stage deformation characteristics, including elastic, nonlinear, and failure stages successively; the structural performance of the joint is better and more in line with the requirements of mid-rise CFS dwellings than conventional joint; (iii) the elastic buckling strength of beam flange can be taken as the elastic limit of the joint, and the ultimate bending moment of the joint is determined by elastic flexural capacity of beam section; (iv) the prediction model and the numerical model can be used to establish an overall model of mid-rise CFS dwelling with consideration of joints’ nonlinear behaviour.

Strengthening of beam - column joint with steel fibre reinforced concrete under seismic loading

Earthquakes not only kill the human beings but the structures too. Considering this above fact, there is a necessity to take care of the beam column joint region in a structure. Under seismic excitation, the bar segment joint district is subjected to even and the vertical shear force extents are normally commonly greater than those in the adjoining bits of the structural segments. In the event that the joint is not precisely nitty gritty, the shaft segment joint may end up plainly frail. To keep this, an adequate control ought to be given in the joint area. The seismic examination and outline technique ought to be utilised as a part of the plan of the building structures and their segments ought to be recommended in the segment. The building structures incorporate finish sidelong and vertical drive opposing frameworks fit for giving satisfactory quality. Stiffness and the vitality dissemination ability to withstand the outline ground movements inside the recommended furthest reaches of twisting and quality request. The plan ground movements are accepted to happen along any even headings of a building structure. This work focuses on behaviour of M20 concrete in beam-column joint subjected to seismic loading, by using steel fibre (1.5%). The specimens detailed as per IS: 456-2000 and IS: 13920-1993 were casted and tested under cyclic and reverse cyclic loading. The parameters analysed were ductility, energy dissipation, load v/s displacement curve, beam-column reinforcement strain and crack pattern. From the experimental investigation, it is found that the fibre reinforced beam-column joint with fibre (1.50% of steel fibre) performs better ductility, load carrying capacity, energy dissipation and strength by 10% more than conventional reinforced beam-column joint.

EFFECT OF USING HIGHLY CONFINED SHORT LAP-SPLICE REINFORCEMENT ON SEISMIC PERFORMANCE OF EXTERIOR BEAM-COLUMN JOINT

The present paper aims to examine the behavior of exterior beam-column joints with different reinforcement details of their columns: continuous and lap splice longitudinal bars were adopted as design parameter. The experimental program was carried out at the Concrete Research Laboratory at Housing and Building Research Center in Egypt; included three exterior reinforced beam column joints that were tested under the effect of quasi-static cyclic loading. One sample was designed according to the provisions of the current seismic design codes and served as a control sample. Columns of the other two samples were detailed with well confined shorter lap spliced longitudinal reinforcement. The overall behavior of the beam-column joints and conclusions are discussed in this paper.

Retrofitting of Reinforced Beam-Column Joints Using Hybrid Laminates

Retrofitting of Reinforced Beam-Column Joints Using Hybrid Laminates

Cyclic Behavior of Exterior Reinforced Beam-Column Joint with Cross-Inclined Column Bars

The poor design practice of beam column joints is compounded by the high demand imposed by the adjoining flexural members (beams and columns) in the event of mobilizing their inelastic capacities to dissipate seismic energy. Unsafe design and detailing within the joint region jeopardizes the entire structure, even if other structural members conform to the design requirements. Beam moment reversals can produce high shear forces and bond breakdown into the joint resulting in cracking of the joint. The most important factors affecting the shear capacity of exterior RC beam-column joints are: the concrete compressive strength, the joint aspect ratio of the joints and number of lateral ties inside the joint. Advanced Reinforcement Pattern (ARP crossed inclined bars) is a feasible solution for increasing the shear capacity of the cyclically loaded exterior beam-column joints. The presence of inclined bars introduces an additional mechanism for shear transfer. External beam- column joints with crossed inclined reinforcement (ARP) modeled in Ansys Workbench showed high strength, and no appreciable deterioration even after reaching the maximum capacity. The load resisting capacity is increased as compared to that of seismic joint (IS: 13920-1993). A parametric study with cross inclined bars at the joint will be studied with different parameters like grade of concrete, tie ratio, joint aspect ratio, energy dissipation, yield ratio etc. A number of models in ANSYS 13.0 workbench and mechanical APDL are developed for different cyclic loads and boundary conditions. The joint with M50 grade of concrete is discussed in this paper.

Comparative Study on Behaviour of Reinforced Beam-Column Joints with Reference to Anchorage Detailing

The ductility capacity, energy dissiaption capapcity and load - deformat ion behaviour of the exterior beam column jo ints constructed with an external anchorage system by provid ing a s mall project ion beyond the column face is evaluated. The evaluation is based on the experimental results of two one fifthe scale exterior bam co lu mn joint specimens tested as part of an extensive experimental program. The control specimen (CS) constructued and detailed as per IS 13920:1993 codal provisions and externally anchoraged specimen (EAS) cast with small projecttion beyond the column face. A s mall axial load was applied to the column port ion of the subasembly and held constant during the test. The free end of the beam was subjected to cyclic load representing a wide range fro m elastic to inelastic loading.By providing an external anchorage system, the reinforcement detailing and concrete placement in the joint region beco me eased and the behavior was better than conventional method of construction. The test results indicate that external anhorage system exhibits excellent behavior in energy dissipation , ductility and load - deformation parameter than for specimens constructed to current design recommendations.