Seismic behavior of beam column joint linkedin slideshare. The beam column joint design should be able to 1 prevent brittle shear failure of the joint 2 maintain integrity of the joint so that the ultimate strength of the connecting beams and columns can be developed. In normal design practice for gravity loads, the design check for joints is not critical and hence not warranted. The main reinforcement provided in the beam are 10 mm diameter bars, 3 nos at top and 3 nos at bottom. Detailing of beamcolumn joint used near the beam column joint for a length of 225 mm and2 legged 4 mm diameter with mild steel bar a spacing of 40 mm cc was provided for the remaining part of the beam. The validity of the proposed method is verified experimentally through a comparative study of the behaviour of seven. The use of stirrups in the joint reinforcement is limited by the maximum value of the ratio of joint reinforcement. A transverse beam is one that frames into the joint in a. The test results of beamcolumn joint specimens were used to develop descriptive equations to characterize the anchorage strength of headed bars. Analysis of reinforced beamcolumn joint subjected to. To compound the problem, the building was long but narrow in plan and required a column free interior. Guidelines for design of joints between steel beams and. Structural members subjected to axial compression and bending are known as beam columns.
Further study of beamcolumnjoint design evaluating the data base, several flaws in the design of beamcolumnjoint were detected, namely the low shear strength and ductility, and shear failure in the joint should be avoided. These recommendations address the proportioning and detailing of these joints, taking into account the interaction of the structural steel and. The functional requirement of a joint, which is the zone of intersection of beams and columns. Construction joints in rcc beams and columns are required when the concreting has to be stopped for the day or more than 30 minutes. Eight 20mm diameter bars were provided, with the bars distributed equally on all faces of the column. Retrofitting rc frames beamcolumn joint cfrp earthquake. While slabs and beams are casted monolithically, so that joint between them are stronger than that of beam and column.
Construction joints in beams and columns their location. In such case, typical construction joints shall be provided so that bond is maintained between set concrete and fresh concrete. In a moment resisting frame, three types of joints can be identified viz. Meher prasad 2 1 project officer, department of civil engineering, iit madras, india 600 036 2 professor, department of civil engineering, iit madras, india 600 036 abstract the beam column joint is the crucial zone in a reinforced concrete moment resisting. The balanced failure of beamcolumn joint is defined at which tensile yielding of longitudinal bars passing through the joint and crushing of concrete start simultaneously. Proposals of beam column joint reinforcement in reinforced. Experimental investigation on the seismic behaviour of beam.
Finite element analysis fea for the beamcolumn joint. Pdf the present work aims to study the seismic performance of exterior beam column joint with nonconventional reinforcement detailing. The cyclic loading is the application of repeated stress intensities at a location on structural components. Shear strengthening of beamcolumn joints article pdf available in engineering structures 247.
Seismic behavior of interior rc beamcolumn joints with. Introduction beam column joints in a reinforced concrete moment resisting frame are crucial zones for transfer of loads effectively between the connecting elements i. The formulation presented establishes compatibility of strains and stress equilibrium. A simple reason is because columns and beams are not casted monolithically together. The stirrups are of 6 mm diameter spaced at 30 mm cc for a distance of 2d, i. Seismic behavior of beam column joints in reinforced. This section gives a brief description of various types of joints and the design of nonseismic joints. Design of beam column joints for seismic resistance, sp123, american concrete institute, farmington hills, mich.
The beamtocolumn joint model in the present investigation three different types of joints were evaluated by the neural networks. The beamcolumn joint is defined as the portion of the column within the. The traditional type 1 joint in structural steel a clear. Pdf the beam column joint is the crucial zone in a reinforced concrete moment resisting frame. Results showed that using steel fibre reinforced concrete sfrc within. On the other hand, the column was reinforced with four bars of 16 mm diameter at each corner of the column crosssection. Throughout this document, the term joint is used to refer to a beamcolumn joint. A basic approach has taken to establish the fundamentals of beamcolumn joint stiffness from which the further research could continue on the following areas. Classification by strength a joint may be classified as nominally pinned, partialstrength or fullstrength comparing its moment resistance m j,rd with the moment resistances of the jointed members. Siddiqui department of civil engineering, king saud university, p. Concrete columnbeam joints by simulated earthquake.
Effect of beam dimensions on structural performance of. From these studied joints it was possible to identify the bolted endplate joints as one of the most adopted joints, see fig. When one beam frames into a vertical face of the column and two other beams frame from perpendicular directions into the joint, then the joint is called as an exterior joint. The results showed that the smareinforced beamcolumn joint specimen was. Beam column a structural member that is subjected to axial compression and transverse bending at the same time. Factors known to affect the behavior of connections, including the effect of lateral restraint present in connections of indeterminate structures as. The degradation that occurs at the location is referred as fatigue degradation.
By far the most common problem, however, is the lapping of bottom beam bars at a column to meet the structural integrity requirements in section 7. This command is used to construct a twodimensional beamcolumnjoint element object. The exterior column was designed for an axial load of 953 kn and a moment of 86. Abract an experiment is reported regarding the effect of using steel fibre reinforced concrete in exterior quarter scale corner beam column joints cast by using m 20 concrete. Mostly, for this large column size is the most effective. Modeling of interior beamcolumn joints for nonlinear.
Anchorage of headed reinforcing bars in exterior beamcolumn joints by yun shao submitted to the graduate degree program in civil, environmental, and architectural engineering and the graduate faculty of the university of kansas in partial fulfillment of the requirements for the degree of doctor of philosophy. Structural welding is a process whereby the parts to be connected are heated and fused with a molten filler metal. In this joint model, the joint shear is transferred via a concrete compression strut as shown in fig. A connection is the joint plus the columns, beams, and slab adjacent to the joint. The beam column joint is the critical zone in a reinforced concrete moment resisting frame. Further research need to establish the theoretical model for semirigidly. The beam column joint specimens were tested under reverse cyclic loading which is applied vertically in y direction at beam end as shown in figure 4. Design of reinforced concrete structures ii column joints beamcolumn joints the function of a beamcolumn joint in a frame is to transfer the loads and moments at the ends of the beams into the columns. A joint may be classified as nominally pinned, semirigid or rigid according to its rotational stiffness. The paper proposes an alternative method for the earthquakeresistant design of hdc external beamcolumn joints which is based on the assumption that the load transferred from the beam and column elements to the joint is predominantly resisted by a diagonal strut mechanism. Many past tests have examined the behavior of joints as found in typical buildi ngs but relatively few tests have been performed on. Traditional type 1 joint detail provided in the plans. When forces larger than these are applied during earthquakes, joints are severely damaged. It is subjected to large forces during severe ground.
Another way is providing steel ties also known as stirrups. Jainb a project officer, department of civil engineering, indian institute of technology madras, chennai, india. Below are some images showing correct method of construction joints to be provided in. Anchorage of headed reinforcing bars in exterior beam. In general, the structural parameters that are vital in. Seshu adluri beamcolumns steel beamcolumns bldg columns with moment connections exposed columns subject to wind columns with eccentric loads beams subject to axial forces and moments design clauses. Tests of reinforced concrete interior beamcolumn joint subassemblage with eccentric beams fumio kusuhara1, keiko azukawa2, hitoshi shiohara3 and shunsuke otani4 summary eccentric beamcolumn joints are used in construction for a reinforced concrete exterior moment resisting frame in buildings. Other failures may also result in inadequacies of structural members. An analytical study of improving beamcolumn joints behavior. Experimental study on the seismic behaviour of strengthened. The mechanics of beamcolumn joints in laterally loaded frame structures are investigated in this paper.
The behaviour and design of beamcolumns are presented within the context of members subjected. Beamcolumn joints with reference to anchorage detailing. The stirrups for both beam and column were mild steel bars of 8 mm diameter and spaced every 100 mm and 150 mm for the beam and the column, respectively. This resulted in dependence on only two column rows leaving no alternative stress paths. The beam column joint has been analysed using stadd pro under seismic zone. Several factors can contribute to beamcolumn joint congestion, such as column verticals that terminate in the beam with hooks and excessive top steel over the column. If the column crosssectional size is insufficient, the concrete in the joint develops diagonal cracks. How do beamcolumn joints in rc buildings resist earthquakes.
A beamcolumn joint is defined as that portion of the column within the depth of the deepest beam that frames into the column. The joint is defined as the portion of the column within the depth of the deepest beam that frames into the column. The element may be used with both twodimensional and threedimensional structures. Cancsas16 classify, strength check 4 checks overall strength interaction formula cl. It is subjected to huge forces during severe ground shaking and its behavior has a significant effect on the response of the structure. The beamcolumn joint is tested under cyclic loading applied at the free end of the beam and axial column load. Beam column joint design details for ansys modeling column size 175 mm x 150 mm, beam size 175 mm d x 150 mmb, strength of concrete fck 20 nmm2.
Research paper effect of key parameters of reinforced. Design of reinforced concrete structures ii column joints. At high level of drift a particular local damage mechanisms developed at the top of the joint region, while the cracks at the column interface kept increasing in width. In rc buildings, portions of columns that are common to beams at their intersections are called beam column joint. Codeconforming code conforming joints oldertype older type beamcolumn beam column connections survey of existing buildings. When a beam each frames into two adjacent vertical faces of a column, then the joint. The equations were compared with test results from previous studies to establish new design criteria for development length that safely allow for the use of headed bars with yield strengths up to. The reinforcement details of the beam column joint specimens are shown in fig. Strengthening of defected beamcolumn joints using cfrp. Rc beam column joint six specimens of external beam column joints with cross sections for both beams and columns of 230 mm. Upon cooling, the structural steel parent metal and weld or filler metal will act as one continuous part. Experimental investigation on the behaviour of beam when it is semirigidly connected with column. Performance of corner rc beamcolumn joints upgraded with cfrp composites under seismic loading saleh h. The rigidity of the connection is less than that of a standard connection but.
Thus a domino type collapse is possible with a failure in one of the joints as the girder spans. In addition, three stirrups were added at the beamcolumn joint. The filler metal is deposited from a special electrode. Repairing damaged joints is difficult, and so damage must be avoided. Pdf classification of reinforced concrete beamtocolumn. The interaction of normal force and bending may be treated elastically or plastically using equilibrium for the classification of crosssection.
The beamcolumn joint is defined as the portion of the column within the depth of the beam that frames into it macgregor 1988. Paulay, behavior of reinforced concrete external beamcolumn joints under cyclic loading. Pdf strength and behaviour of exterior beam column joints with. Mosier joint failures studies of older oldertype type joints. Appendix a beamcolumn joint database the beamcolumn joint database is a collation of the results of tests performed on bridge beamcolumn joint specimens relevant to the purposes of this study. When four beams frame into the vertical faces of a column, the joint is called as an interior. The detailing of beamcolumn joints of rc frame structures in regions of high earthquake risk is normally governed by code provisions gb 500102002, aci 318. The suggested repair procedure was applied to the tested specimen. This paper proposes a new set of general and rational. The reinforcement detailing for three of the specimens is according to is4562000 nonductile, and the remaining three specimens are per is920 1993.
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