• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.5
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• pp.1-9
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• 2007

This study summarizes the results of a research project aimed at investigating the inelastic rotation capacity of beam-column connections of reinforced concrete moment frames. A total of 91 test specimens for beam-column joint connections were examined in detail, and 28 specimens were classified as special moment frame connections based on the design and detailing requirements in the ACI 318-02 Provisions. Then the acceptance criteria, originally defined for steel moment frame connections in the AISC-02 Seismic Provisions, were used to evaluate the joint connections of concrete moment frames. Twenty-seven out of 28 test specimens that satisfy the design requirements for special moment frame structures provide sufficient strength and are ductile up to a plastic rotation of 0.03 rad. without any major degradation in strength. Joint shear stress, column-to-beam flexural strength ratio, and transverse reinforcement ratio in a joint all play a key role in good performance of the connections.

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.629-639
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• 1998

This paper summarizes the results of full-scale cyclic seismic performance tests on three column-tree type steel moment connections. Each test specimen consisted of a $H-600{\times}200$ beam and a $H-400{\times}400$ column of SS41 (SS400). Key parameter included was column PZ (panel zone) strength relative to beam strength. The seismic performance of specimen with stronger PZ tended to be inferior. Total plastic rotations available in the specimens ranged from 1.8 to 3.0 (% rad). The limited test results in this study seem to support the speculation that permitting PZ yielding shall be more beneficial to enhancing total plastic rotation capacity of the moment connection. Beam flange fracture across the heat affected zone and divot-type pullout of the column flange were observed in the tests. A conceptual mechanical model consistent with observed test results was also sought.

• Journal of Korean Association for Spatial Structures
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• v.4 no.4 s.14
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• pp.55-63
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• 2004

Double angle connections are commonly used for the construction of the low-rise steel framed buildings. Several experimental tests lave been conducted to investigate the effect of the number of bolts on the rotational stiffness of a double angle connection. Several parameters are obtained by performing regression analysis. An analytical model has been introduced to calculate the initial stiffness of a double angle connection in this research.

• Journal of Korean Society of Steel Construction
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• v.17 no.5 s.78
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• pp.569-580
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• 2005

The postbeam joint connection of the existing steel structure moment flexible frame system did not produce sufficient seismic resistance during the earthquakes in Northridge and Kobe, and it sustained brittle fracturing on the joint connection. This study was performed to execute the high-tensile bolt share connection of H-beams web and the full-scale experiment as a parameter of the existing reinforcement of H-flange rib, by making the shape of the existing joint connection. This experiment was performed to determine the extent of the decrease of the number of high-tensile bolts and how to improve workability of the two-phase shear connection of web beam. In addition, this study was performed to enhance the seismic resistant capacity through the enforcement of rib plates. As a result of the experiment of two-phase shear connection of H-beam web and of joint connection to be reinforced by rib plates, the results of this study showed that the initial stiffness, energy-dissipation capacity, and rotational capacity of plasticity was higher than the existing joint connection. As to the rate of increasing the strength and deformation capacity, there were differences between the tension side and compression side because of the position of shear tap. However, as a whole, they have shown excellent seismic resistant capacity. Also, all the test subjects exceeded 4% (rate of delamination), about 0.029 rad (total plastic capacity), and about 130% (maximum strength of joint connection) of fully plastic moment for the original section. Accordingly, this study was considered as it would be available in the design more than the intermediate-level of moment flexible frame.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.513-523
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• 2010

For continuous I-girder bridges, a large negative bending moment is generated near pier region so that plastic hinge is first formed at this point. Then, the bending moment is redistributed when the I-girder has enough flexural ductility (or rotational capacity). However, for I-girder with high strength steel, it is known that the flexural ductility is considerably decreased by increasing the yield strength of material. Thus, it is necessary to conduct a study for guaranteeing proper flexural ductility of I-girder with high-strength steel. In this study, the evaluation of flexural ductility of negative moment region of I-girder with high strength steel where yield stress of steel is 680 MPa is presented based on the results of finite element analysis and experiment. From the results, it is found that the flexural ductility of the I-girder is significantly reduced due to the increase of elastic deformation and the decrease of plastic deformation ability of the material when the yield strength increases. In this study, the method to improve the flexural ductility of I-girder with high strength steel is proposed by an unequal installation of cross beam and an optimal position of cross beam is also suggested. Finally, the effects of the unequal installation of cross beam on the flexural ductility are discussed based on the experimental results.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.829-838
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• 2008

In this study, cyclic tests of beam-column connections composed with members applicable to the domestic low-middle rise steel buildings were conducted to develop seismic connection details and its evaluation. Connection types and material properties of the steel were testing variables and the difference between the newly developed seismic rolled section (SHN490) and existing rolled section (SM490) was also investigated. Distributions of the yield strength and the ultimate strength of the SHN490 rolled section were relatively uniform comparing to those of the SM490 rolled section Brittle fracture in the weldments of the test specimens was not observed. Instead, fracture occurred at heat-affected zones or the stress-concentrated point near the weld access hole of the beam flanges. In the case of identical rolled-section specimens, the rotational capacity and dissipated energy of the WUF-W connection was larger than those of the WUF-B connection. In the case of identical connection types, the rotational capacity and dissipated energy of the SHN490 section connection was larger than those of the WUF-B section connection.

• Journal of Korean Society of Steel Construction
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• v.18 no.1
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• pp.59-69
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• 2006

This paper presents test results on reduced beam section (RBS)program addressed panel zone (PZ) strength as the key variables. PZ strength has been much debated issue for several decades. A desirable range of PZ strength has not yet been proposed despite the fact that a significant amount of RBS test data is available. Test results from this study and by others showed that panel zones could easily develop a plastic rotation of 0.01 radian without causing distress to the beam flange groove welds. At this deformation level, the amount of beam distortion (i.e., buckling) was about one half that developed in strong PZ specimens. A criterion for a balanced PZ strength that improves the plastic rotation capacity while reducing the amount of beam buckling is proposed.

• Journal of Korean Society of Steel Construction
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• v.23 no.2
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• pp.147-158
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• 2011

The purpose of this research was to analyze the connections of the seismic-performance values for domestic-performance-based designs. Basic research on the performance design method has been increasing of late, along with performance-based organization investigations. These investigations concern the performance level state of steel structure buildings. According to the performance limit state, seismic-performance values should be presented as appropriate steel structure engineering amounts. The first step, based on the full-scale steel structure experiments, involves researching on the making of a basic document. The moment-rotation angle relationship results of the experiment on the moment-frame connection were used to assort the functional and undamaged limits, which were assumed to be less than the yield moment. Moreover, the repairable and safety limits, which were assumed to exist between the yield and maximum moments, were assorted by investigating the accumulated plastic deformation ratio.

• Journal of Korean Society of Steel Construction
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• v.26 no.2
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• pp.133-142
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• 2014

Double split tee connection is a full strength-partial restrained connection that suitable for ordinary moment frame and special moment frame which demonstrates behavior characteristics depending on the stiffness ratio of columns and beams, changes in the geometric shape of the T-stub, number of fasteners and effect of panel zone. For the double split tee connection to ensure structurally safe behavior, it needs to exhibit sufficient strength, stiffness and ductile capacity. This study sought to investigate the effects of the moment-rotation angle relationship of the double split tee connection and to evaluate the initial rotational stiffness of the double split tee connection depending on changes in the geometric shape of the T-stub. To this end, two different double split tee connection specimens are experimented which designed to change geometric parameter values (${\alpha}^{\prime}$) of the T-stub, and a three-dimensional finite element analysis was performed.

• Computational Structural Engineering
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• v.11 no.1
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• pp.46-57
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• 1998

노스리지 지진하의 모멘트 저항 강 뼈대 구조물에 대한 사례연구결과를 요약하면 다음과 같다. 1) 탄성과 비탄성 동적해석 방법의 신뢰도가 구조물의 동적거동의 모형화에 크게 영향을 받는다는 것을 알 수 있었고 구조물의 동적거동의 모형화를 위한 보다 개선된 지침과 기준의 필요성이 부각되었다. 2) 비탄성 횡방향 정적해석은 6층높이의 건물까지는 비탄성동적해석과 유사한 결과를 보였으나 10층 이상의 건물에서는 고차 모드 효과를 고려하지 못하여 상당히 상이한 결과를 나타냈다. 3) 응답스펙트럼 해석은 노스리지 지진하에서 탄성 시간이력 해석에 비하여 100%까지 상이한 결과를 보였다. 특정지진에 대한 구조물거동의 상세조사시 응답 스펙트럼 해석 대신 시간이력해석을 수행하는 것이 바람직하다. 4) 탄성 부재력의 저항능력 비와 소성 회전각 등의 거동지수 등은 현존하는 건물의 연결부 손상을 검사하기 위한 지침을 마련하는데 도움을 줄 수 있지만 특정 연결부를 검사에서 배제시키는 유일한 근거로 사용되어서는 안될 것으로 판단된다.