• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.453-454
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• 2009

In this dissertation, experimental program was carried out to study the hysteretic behavior of the reinforced different floor type interior beam-column joint repeated cyclic loads under seismic actions. The test results was as follow. The reinforced interior beam-column joint, designed by the different floor type, was increased energy dissipation capacity and maximum load carrying capacity according to the increase of different floor in comparison to standard specimen. And it was also dissimilar to failure mode adjacent to joint region. energy dissipation capacity of each specimen, designed by the different floor type, was increased 1.1${\sim}$1.35 times in comparison to standard specimen.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.6
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• pp.72-81
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• 2014

This paper reports the test results of reinforced concrete exterior beam-column joints with high-strength concrete. The main parameters of eight specimens were joint failure modes, the compressive strength of concrete, and the head shapes of steel bars. All specimens were designed according to ACI 352R-02 design recommendations. Two types of failure modes were considered; J-failure and BJ-failure. The longitudinal steel bars were anchored by 90 degree standard hooks or headed reinforcement. Experimental results indicated that the current ACI design recommendation limited by the compressive strength of concrete somewhat underestimated the strength of beam-column joints with high-strength concrete. In the specimens showed joint shear failure, the strength of beam-column joints with headed bars was approximately 10 percent higher than that of joints with 90 degree standard hooks.

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.789-799
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• 1998

The purpose of this study is to propose the prototypes of bolted end plate moment connection between CFT column and H-beam sections. Nine different types of bolt are designed in this study. The shapes of those bolt are straight. bent, hooked or stud-type. The end plate moment connection between CFT column and H-beam sections which are jointed by those bolts are studied experimentally to compare their performances. The simple beam bending tests are carried out to investigate the structural behavior of beam-to-column connections. The experimental results show that some of the bolted end plate connection types have quite good performance in the structural behavior but still have a lot of week points to be solved for the efficiency of construction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.1
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• pp.73-80
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• 2022

In this study, details of NRC beam-column connections were developed in which beam and columns pre-assembled in factories using steel angles were bolted on site. The developed joint details are NRC-J type and NRC-JD type. NRC-J type is a method of tensile joining with TS bolts to the side and lower surfaces of the side plate of the NRC column and the end plate of the NRC beam. NRC-JD type has a rigid joint with high-strength bolts between the NRC beam and the side of the NRC column for shear, and with lap splices of reinforcing bar penetrating the joint and the beam main reinforcement for bending. For the seismic performance evaluation of the joint, three specimens were tested: an NRC-J specimen and NRC-JD specimen with NRC beam-column joint details, and an RC-J specimen with RC beam-column joint detail. As a result of the repeated lateral load test, the final failure mode of all specimens was the bending fracture of the beam at the beam-column interface. Compared to the RC-J specimen, the maximum strength of the specimen by the positive force was 10.1% and 29.6% higher in the NRC-J specimen and the NRC-JD specimen, respectively. Both NRC joint details were evaluated to secure ductility of 0.03 rad or more, the minimum total inter-story displacement angle required for the composite intermediate moment frame according to the KDS standard (KDS 41 31 00). At the slope by relative storey displacemet of 5.7%, the NRC-J specimen and the NRC-JD specimen had about 34.8% and 61.1% greater cumulative energy dissipation capacity than the RC specimen. The experimental strength of the NRC beam-column connection was evaluated to be 30% to 53% greater than the theoretical strength according to the KDS standard formula, and the standard formula evaluated the joint performance as a safety side.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.641-652
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• 2004

The strong beam-to-column axis connections in steel structures have been studied for a long time to develop the strength and resistance of the connections. There have been very few studies, however, related to weak axis connections. Domestically, the bracket-type connection is commonly used in weak axis connections to elevate the efficiency of the constructions when the steel structures are constructed. The bracket-type connection detail has been applied moderately to weak axis connections. Therefore, the bracket-type connection in weak axis connections might be brittle and over-designed. The results of this study showed that the welding on the web of the column and the beam was unnecessary. In addition, this study confirmed that the new weak axis connection proposed in this study was superior to the previous connection in terms of strength and ductility.

• Journal of Korean Society of Steel Construction
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• v.27 no.3
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• pp.299-310
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• 2015

CFT(Concrete-Filled Tube) structures have problems at processing cause closed section and concrete filling problems. In this study, a CFT structure that uses different types of diaphragms in its upper and lower connections to improve the concrete filling was tested and analyzed via the FEM program. Implementation of variable analysis of EP-T type to find out the reason that effect on the resistance force of the connection. As a result, through experiments and analysis investigated the structural characteristics of circular CFT beam-to-column connection.

• Journal of Korean Society of Steel Construction
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• v.12 no.4 s.47
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• pp.437-443
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• 2000

In order to clarify the behavior of beam-to-concrete filled steel tube column under cyclic loading condition, experimental studies were carried out on shear connections. Test parameters of this study are the width-to-thickness ratio and the effect on beams with or without slab and diaphragm. Test results show that the moment-rotation relationships of connections without slab are in the range of AISC regulation of pinned connections and the rotation capacity of connection is dependent upon the width-to-thickness ratio of the column.

• Journal of Korean Society of Steel Construction
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• v.23 no.1
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• pp.83-97
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• 2011

In this study, the seismic details of a concrete-encased, U-shaped steel beam-to-RC column connection were developed. Three specimens of the beam-to-column connection were tested under cyclic loading to evaluate the seismic performance of the connection. The test parameters were the beam depth and the column section shape. The depths of the composite beams were 610 and 710 mm, including the slab depth. For the RC columns, a square section and a circular section were used. Special details using diagonal re-bars and exterior diaphragm plates were used to strengthen the connections with the rectangular and circular columns, respectively. The test results showed that the specimens exhibited good strength, deformation, and energy dissipation capacities. The deformation capacity exceeded 4% interstory drift angle, which is the requirement for the Special Moment Frame.

• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.325-335
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• 2005

This study tackles the development of an improved detail of partially restrained CFT square column-to-beam connection and the evaluation of its mechanical behavior under monotonic loading. The connection is designed to strengthen shearing capacity at the bottom of the connection due to the ultimate behavior of PR-CC by its detail of the bottom connection and simplify the fabrication process. The suggested connection is the welded bottom beam flange connection(M-2) and is compared with the existing PR-CC of bolted seat angle connection(M-1). Two specimens were fabricated in actual size and tested under monotonic loading. Based on the test results, the welded bottom beam flange connection exhibited about 85% of the stiffness of steel beam. It was similar to the bolted seat angle connection and behaved as PR-CC. The specimen of the supposed connection type failed at the shear connection of web but was similar to the bolted seat angle connection until the failure. It obtained sufficient stiffness and capacity through the reinforcingsteel and the capacity and deformational ability equivalent to the full-plastic moment through the anchor inside the steel tube at the web connection. So, it can be said that the suggested connection exhibits sufficient ductile behavior.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.2
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• pp.84-91
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• 2022

This study investigated the behavior of out-of-plane skewed moment connections that were designed as IMFs, as per the Korean standards. A total of 14 finite element models were constructed with the consideration of two types (single- and double-sided connections) and four levels of skew angle (0°, 10°, 20°, and 30°). The results indicated that the skewed connections considered in this study met the acceptance criteria for IMFs given by the codes. However, the load-carrying capacities of skewed connections were decreased as the skew angle increased. For the connection with a skew angle of 30°, the peak load was noted to be 13% less and the energy dissipation capacity could be 26% less than that of non-skewed connection. In addition, because of the skewed nature, the stress distribution in the skewed beam flange near the connection was asymmetric and the stresses were concentrated on the beam inner flange. Column twisting induced by the skewed configuration was very small and negligible in the beam and column combination considered in this study.