• Steel and Composite Structures
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• 제4권4호
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• pp.303-315
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• 2004

Frame composed of concrete-filled steel tubular columns and I-shaped steel beam has been researched in order to development reasonable connection details. The present paper describes the results of an experimental program in four different connection details. The connection details considered include through-bolt between I-shaped steel beams and concrete-filled steel tubular columns and two details of welded connections. One of the welded connection details is stiffened by angles welded in the interior of the profile wall at the beam flange level. The specimens were tested in a cruciform loading arrangement with variable monotonic loading on the beams and constant compressive load on the column. For through-bolt details, the contribution of friction and bearing were investigated by embedding some of the bolts in the concrete. The results of the tests show that through-bolt connection details are very ductility and the bearing is not important to the behavior of these moment connections. The angles welded in the interior of the profile wall increase the strength and stiffness of the welded connection detail. In addition, the behavior curves of these connections are compared and some interesting conclusions are drawn. The results are summarized for the strength and stiffness of each connection.

• Structural Engineering and Mechanics
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• 제24권3호
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• pp.307-321
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• 2006

This paper is concerned with the behaviour of steel and concrete composite joints subjected to reversal of loading. Three cruciform composite joint specimens and one bare steel joint specimen were tested so that one side of the beam-to-column connection was under negative moment and another side under positive moment. The steelwork beam-to-column connections were made of bolted end plate with an extended haunch section. Composite slabs employing metal decking were used for all the composite joint specimens. The moment-rotation relationships for the joints were obtained experimentally. Details of the experimental observations and results were reported.

• Steel and Composite Structures
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• 제50권6호
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• pp.627-641
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• 2024

This paper presents an experimental and numerical study to investigate the behavior of the precast segmental concrete beams (PSCBs) utilizing high-strength concrete (HSC) connected in the zone of the maximum bending moment using steel extended endplate connections (EECs). The experimental study consisted of five beams as follows: The first beam was the control beam for comparison, which was an unconnected one-piece beam made of HSC. The other four other beams consisted of two identical pieces of precast concrete. An important point to be noted is that at the end of each piece, a steel plate was used with a thickness of 10 mm. Moreover, this steel plate was welded to the lower and upper reinforcing bars of the beam. Furthermore, the steel plate was made to connect the two pieces using the technique of EECs. Several variables were taken in these four beams, whether from the shape of the connection or enhancing the behavior of the connection using the post-tensioning technique. EECs without stiffeners were used for some of the tested beams. The behavior of these connections was improved using stiffeners and shear bolts. To get accurate results, a comparison was made between the behaviors of the five beams. Another important point to be noted is that Abaqus and SAP2000 programs were used to investigate the behavior of PSCBs and to ensure the accuracy of the modeling process which showed a good agreement with the experimental results. Additionally, the simplified modeling using SAP2000 was able to model the nonlinear behavior of PSCBs connected using steel EECs. It was found that the steel pre-tensioned bolted EECs, reinforced with steel stiffeners and shear anchors, could be used to connect the precast HSC segmental beams via the internal pre-stressing technique.

• Steel and Composite Structures
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• 제28권5호
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• pp.559-571
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• 2018

In current engineering practice, circular concrete-filled steel tubular (CFST) columns have been used as effective structural components due to their significant structural and economic benefits. To apply these structural components into steel-concrete composite moment resisting frames, increasing number of research into the column-base connections of circular CFST columns have been found. However, most of the previous research focused on the strength, rigidity and seismic resisting performance of the circular CFST column-base connections. The present paper attempts to investigate the demountability of bolted circular CFST column-base connections using the finite element method. The developed finite element models take into account the effects of material and geometric nonlinearities; the accuracy of proposed models is validated through comparison against independent experimental results. The mechanical performance of CFST column-base connections with both permanent and demountable design details are compared with the developed finite element models. Parametric studies are further carried out to examine the effects of design parameters on the behaviour of demountable circular CFST column-base connections. Moreover, the initial stiffness and moment capacity of such demountable connections are compared with the existing codes of practice. The comparison results indicate that an improved prediction method of the initial stiffness for these connections should be developed.

• 한국지진공학회논문집
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• 제7권3호
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• pp.69-77
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• 2003

본 연구는 8개의 RBS(reduced beam section) 내진 철골모멘트접합부의 실물대 실험결과를 요약한 것이다. 실험의 주요변수는 보 웨브 접합법 및 패널존 강도를 택하였다. 균형 패널존 시험체는 접합부의 내진성능을 감소시키지 않으면서, 보와 패널존이 함께 균형적으로 지진에너지를 소산시키도록 설계하여 값비싼 패널존 보강판(doubler plates)의 수요를 줄이고자 시도한 것이다. 보 웨브를 용접한 시험제는 모두 특별 연성모멘트골조에서 요구되는 접합부 회전능력을 충분히 발휘하였다. 반면 보 웨브를 볼트 접합한 시험체는 조기에 스캘럽을 가로지르는 취성파단이 발생하는 열등한 성능을 보였다. 보 그루브 용접부 자체의 취성파괴가 본 연구에서와 같이 양질의 용접에 의해 방지되면, 스켈럽 부근의 취성파단이 다음에 해결해야 할 문제로 대두되는 경향을 보인다. 보 웨브를 볼팅한 경우에 접합부 취성파단의 빈도가 월등히 높은 이유를 실험 및 해석결과를 토대로 제시하였다. 측정된 변형도 데이터에 의할 때, 접합부의 전단력 전달메카니즘은 흔히 가정하는 고전 휨이론에 의한 예측과 전혀 다르다. 이는 전통적 보 웨브 설계법을 재검토할 필요가 있음을 시사하는 것이다. 아울러, 접합부에서 요구되는 바람직한 거동기준을 제시하고 이를 근거로 균형 패널존의 강도범위에 대한 예비적 추정치를 제시하였다.

• 한국강구조학회 논문집
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• 제14권4호
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• pp.557-566
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• 2002

본 논문은 4개의 철골모멘트 접합부에 대한 반복재하 실물대(實物大) 실험결과를 요약한 것이다. 주요 실험변수는 기둥과 보의 접합방식 (볼트접합 대 용접) 및 패널존의 강도 (강한 패널존 대 중간강도 패널존)이다. 중간 패널존 강도를 갖는 시험체는 패널존과 RBS 영역 모두에서 균형잡힌 방식으로 에너지가 소산되도록 고려하여 설계된 것으로 패널존 보강비용을 줄이고자 시도한 경우이다. 보웨브가 용접으로 접합된 경우의 시험체들은 특별연성모멘트골조에 요구되는 충분한 접합부 회전성능을 보여 주었지만, 웨브를 볼트로 접합한 시험체들은 스캘럽을 가로지르는 보플랜지의 조기 취성파괴로 인해 열등한 내진성능을 노출하였다. 보웨브를 볼트로 접합하면 비용을 줄일 수 있으나 원래 보단면의 전소성모멘트를 기둥에 전달하기 어려운 것으로 나타났다. 본 연구에서 적용된 것과 같이 양질의 용접시공에 의해 일단 그루브 용접부 자체의 취성파괴 문제가 해결되고 나면, 용접접근공내에 위한 보플랜지 모재의 파단이 다음의 문제로 대두됨을 알 수 있다. 용접접근공 내의 보 플랜지 파단문제를 역학적인 측면에서 이해하는데 도움이 되는 해석적 연구도 수행되었다.

• Steel and Composite Structures
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• 제1권1호
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• pp.33-50
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• 2001

In this paper an experimental study is performed on end-plate type joints. The test arrangement represents a column-base joint of a steel frame. Altogether six specimens were tested, each of them subjected to cyclic loading. The specimens were carefully designed by performing detailed preliminary calculations so that they would present typical behaviour types of end-plate joints. On the basis of the experimentally established moment-rotation relationship, the cyclic characteristics of each specimen have been calculated and compared to one another. The results are evaluated, qualitative and quantitative conclusions are drawn.

• Steel and Composite Structures
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• 제16권2호
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• pp.157-185
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• 2014

This paper examines the behaviour of two types of practical open beam-to-tubular column connection details subjected to combined moment, axial and/or shear loads. Detailed continuum finite element models are developed and validated against available experimental results, and extended to deal with flexural, axial and shear load interactions. A numerical investigation is then carried out on the behaviour of selected connections with different stiffness and strength characteristics under various load combination scenarios. The influence of applied levels of axial tensile or compressive loads on the bending stiffness and capacity is examined and discussed. Additionally, the interaction effects between shear forces and co-existing bending and axial loads are examined and shown to be comparatively insignificant in terms of stiffness and capacity in most cases. It is also shown that the range of connections considered in this paper can provide rotational ductility levels in excess of those required under typical design scenarios. Based on these findings, a simplified component-based representation is proposed and described, and its ability to represent the connection response under combined loading is verified using results from detailed numerical simulations.

• 한국지진공학회논문집
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• 제2권4호
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• pp.115-122
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• 1998

고력볼트로서 슬립이 발생치 않도록 설계된 철골모멘트골조의 보 이음부의 내진거동을 반복재하 실물대 실험을 통하여 평가하였다. 예상과는 달리 모메트 접합부가 극한 소성강도에 도달하기 훨씬 이전에 보 이음부의 슬립이 발생하였다 실험을 통하여 관측된 마찰계수는 규준 공칭값의 50-60%에 불과하였다. 그러나 보 플랜지의 열영향부가 파단에 이르기 까지 슬립 이후의 지압거동을 통하여 증가되는 반복하중을 성공적으로 모멘트접합부로 전달하였다. 즉 반복하중 하에서도 보 이음부의 슬립이 곧바로 구조적 일체성의 상실로 이어지지는 않음이 관측되었다 볼토구멍을 공제한 보 플랜지 유효단면적의 전강도에 기준한 전통적 보 이음부 설계법에 의할 경우 모멘트 접합부의 소성강도 발현 이전에 보 이음부의 슬립발생 가능성이 높다 본 연구에서는 역량설계 개념에 기초하여 강진 작용시의 보 이음부의 설계와 관련한 추가 고려사항을 제안하였다.

• Steel and Composite Structures
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• 제8권5호
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• pp.403-421
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• 2008

The design provisions for semi-rigid steel frames have been incorporated in codes of practice for steel structures. In order to do the same, it is necessary to know the experimental moment-relative rotation (M-${\theta}_r$) behaviour of beam-to-column connections. In spite of numerous publications and collection of several connection databases, there is no unified approach for the semi-rigid design of steel frames. Amongst the many connection models available, the Frye-Morris polynomial model, with its limitations reported in the literature, is simple to adopt at least for the linear design space. However this model requires more number of connection tests and regression analyses to make it a realistic prediction model. In this paper, 3D nonlinear finite element (FE) analysis of beam-column connection specimens, carried out using ABAQUS software, for evaluating the M-${\theta}_r$ behaviour of semi-rigid top and seat-angle (TSA) bolted connections are described. The finite element model is validated against experimental behaviour of the same connection with regard to their moment-rotation behaviour, stress distribution and mode of failure of the connections. The calibrated FE model is used to evaluate the performance of the Frye-Morris polynomial model. The results of the numerical parametric studies carried out using the validated FE model have been used in proposing modifications to the Frye-Morris model for TSA connection in terms of the powers of the size parameters.