• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.249-258
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• 2006

In this paper, deformation capacity of steel moment connections with RHS column was investigated. Initially, non-linear finite element analysis of five bate steel beam models was conducted. The models were designed to have different detail at their beam-to-column connection, so that the flexural moment capacity was different respectively. Analysis results showed 4hat the moment transfer efficiency of the analytical model with RHS-column was poor when comparing to model with WF(Wide flnage)-column due to out-of-plane deformation of the RHS-column flange. The presence of scallop and thin plate of RHS column was also a reason of the decrease of moment transfer efficiency, which would result in a potential fracture of tile steel beam-to-column connections. Further test on beam-to-column connections with RHS column revealed that the moment transfer efficiency of a beam web decreased due to the out-of-plane deformation of column flange, which led to premature failure of the connection.

• Steel and Composite Structures
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• v.28 no.6
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• pp.719-734
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• 2018

Prior to the introduction of modern seismic guidelines, it was a common practice to provide straight bar anchorage for beam bottom reinforcement of gravity load designed building. Exterior joints with straight bar anchorages for beam bottom reinforcements are susceptible to sudden anchorage failure under load reversals and hence require systematic seismic upgradation. Hence in the present study, an attempt is made to upgrade exterior beam-column sub-assemblage of a three storied gravity load designed (GLD) building with single steel haunch. Analytical formulations are presented for evaluating the haunch forces in single steel haunch retrofit. Influence of parameters that affect the efficacy and effectiveness of the single haunch retrofit are also discussed. The effectiveness of the single haunch retrofit for enhancing seismic performance of GLD beam-column specimen is evaluated through experimental investigation under reverse cyclic loading. The single steel haunch retrofit had succeeded in preventing the anchorage failure of beam bottom bars of GLD specimen, delaying the joint shear damage and partially directing the damage towards the beam. A remarkable improvement in the load carrying capacity of the upgraded GLD beam-column sub-assemblage is observed. Further, a tremendous improvement in the energy dissipation of about 2.63 times that of GLD specimen is observed in the case of upgraded GLD specimen. The study also underlines the efficacy of single steel haunch retrofit for seismic upgradation of deficient GLD structures.

• Earthquakes and Structures
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• v.16 no.5
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• pp.533-546
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• 2019

This study presents an experimental investigation on six beam-column joint specimens under the lateral cyclic loading. The aim was to explore the effectiveness of steel fiber-reinforced concrete (SFRC) in reducing the transverse shear stirrups in beam-column joints of the reinforced concrete (RC) frames with strong-columns and weak-beams. Two RC and four SFRC specimens with different types of reinforcement detailing and steel fibers of volume fraction in the range of 0.75-1.5% were tested under gradually increasing cyclic displacements. The main parameters investigated were lateral load-resisting capacity, hysteresis response, energy dissipation capacity, stiffness degradation, viscous damping variation, and mode of failure. Test results showed that the diagonally bent configuration of beam longitudinal bars in the beam-column joints resulted in the shear failure at the joint region against the flexural failure of beams having straight bar configurations. However, all SFRC specimens exhibited similar lateral strength, energy dissipation potential and mode of failure even in the absence of transverse steel in the beam-column joints. Finally, a methodology has been proposed to compute the shear strength of SFRC beam-column joints under the lateral loading condition.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.251-254
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• 2005

This study will have to define the shear strengthening effects of steel fiber in beam and column levels, as well as to suggest estimation method of maximum shear capacity of structural members. From review of literature surveys and perform structural member test results, following conclusion can be made; In beam level, steel fiber strengthening factor is suggested from the tensile splitting test results and beam test results. After suggesting shear capacity of beam without stirrups and beam with stirrups by proposed steel fiber strengthening factor, proposed equation is possible to evaluate the shear capacity of beam. In column level, with column test results and proposed steel fiber strengthening factor, shear capacity equation of steel fiber reinforced concrete in column is suggested.

• Journal of the Korean Society of Safety
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• v.21 no.2 s.74
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• pp.57-62
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• 2006

Recent trends in the construction of building frame feature the use of composite steel concrete members. One of such system, RCS(Reinforced Concrete column and Steel beam) system, is known as a type of system to maximize the structural and economic benefits in the most efficient manner. This paper is focusing on an study of ultimate shear strength estimation of the interior beam-column joints of RCS system, with reinforced concrete column and steel beam. Current design methods as well as the majority of the previous researches for ultimate shear strength of the interior beam-column joint of RCS system are not easy to apply actual manner. There is a need to propose the rational macro models based on analytical approach. In this study, design method variables for interior beam-column joints of RCS system is studied assuming shear resistance of steel web panel, diagonal concrete strut mechanism and truss mechanism. Finally, calculated results based on the proposed design model are compared with test data.

• Journal of Korean Society of Steel Construction
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• v.8 no.4 s.29
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• pp.85-94
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• 1996

This paper investigated structural behaviors of joint of concrete filled steel tube column and P.C reinforced concrete beam through a series of hysteretic behavior experiment. The results are summarised as follows: (1) The joint stiffness of concrete filled square steel tube column and P.C reinforecd beam was higher than that of concrete filled circular steel tube column and P.C reinforecd beam, and it was decreased as the increase of the number of hysteretic cycle. (2) The aspects of the hysteretic behavior in the joint was stable as the increase of the number of hysteretic cycle, and rotation resisting capacity of joint of concrete filled square steel tube column and P.C reinforced concrete beam was higher than those of the concrete filled circular steel tube column and P.C reinforced concrete beam. (3) Some restriction must be put upon the ratio of axial force in this joint model because the load carrying capacity was decreased by flexural and flexural-torsional buckling in case of the ratio of axial force 0.6. (4) The emprical formula to predict the ultimate capacity of joint model to superimpose shearing strength of steel web(H section) and bending strength of reinforced concrete beam was expected.

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.741-748
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• 1998

Experimental studies were carried out with test parameters: diaphragm yield type and beam yield type, the opening hole size of inner steel diaphragm, and the existence of slab in order to understand the behavior of beam-to-concrete filled steel tube column rigid connections under cyclic loading condition. Test results show that the connections have good rotational capacity when the beam yields first and the joints should be designed such that the beam yields prior to the inner diaphragms.

• Advances in concrete construction
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• v.3 no.3
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• pp.237-250
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• 2015

Beam-column joints are highly vulnerable locations which are to be designed for high ductility in order to take care of unexpected lateral forces such as wind and earthquake. Previous investigations reveal that the addition of steel fibres to concrete improves its ductility significantly. Also, due to presence of slab the strength and ductility of the beam increases considerably and ignoring the effect of slab can lead to underestimation of beam capacity and defiance of strong column weak beam concept. The influence of addition of steel fibres on the strength and behaviour of steel fibre reinforced high performance concrete (SFRHPC) interior beam-column-slab joints was investigated experimentally. The specimens were subjected to reverse cyclic loading. The variable considered was the volume fraction of crimped steel fibres i.e., 0%, 0.5% and 1.0%. The results show that the addition of steel fibres improves the first crack load, strength, ductility, energy absorption capacity and initial stiffness of the beam.

• Steel and Composite Structures
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• v.26 no.1
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• pp.31-44
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• 2018

This paper reports a novel steel beam-to-column connection suitable for use in the weak axis of I-section column. Monotonic and cyclic loading experimental investigations and numerical analysis of the proposed weak-axis connection were conducted, and the calculation procedure of the beam-column relative rotation angle and plastic rotation angle was developed and described in details. A comparative analysis of mechanical property and steel consumption were employed for the proposed I-section column weak-axis connection and box-section column bending connection. The result showed that no signs of fracturing were observed and the plastic hinge formed reliably in the beam section away from the skin plate under the beam end monotonic loading, and the plastic hinge formed much closer to the skin plate under the beam end cyclic loading. The fracture of welds between diaphragm and skin plate would cause an unstable hysteretic response under the column top horizontal cyclic loading. The proposed weak-axis connection system could not only simplify the design calculation progress when I-section column is adopted in frame structural design but also effectively satisfy the requirements of 'strong joint and weak member', as well as lower steel consumption.

• Steel and Composite Structures
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• v.25 no.2
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• pp.245-255
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• 2017

The performance of an Industrialised Building System (IBS) consists of prefabricated reinforced concrete components, is greatly affected by the behaviour of the connection between beam and columns. The structural characteristics parameters of a beam-to-column connection like rotational stiffness, strength and ductility can be explained by load-rotation relationship of a full scale H-subframe under gravitational load. Furthermore, the connection's degree of rigidity directly influences the behaviour of the whole frame. In this research, rotational behaviour of a patented innovative beam-to-column connection with unique benefits like easy installation, no wet work, no welding work at assembly site, using a hybrid behaviour of steel and concrete, easy replacement ability, and compatibility with architecture was investigated. The proposed IBS beam-to-column connection includes precast concrete components with embedded steel end connectors. Two full-scale H-subframes constructed with a new IBS and conventional cast in-situ reinforced concrete system beam-to-column connections were tested under incremental static loading. In this paper, load-rotation relationship and ratio of the rigidity of IBS beam-to-column connection are studied and compared with conventional monolithic reinforced concrete connection. It is concluded that this new IBS beam-to-column connection benefits from more rotational ductility than the conventional reinforced concrete connection. Furthermore, the semi-rigid IBS connection rigidity ratio is about 44% of a full rigid connection.