• Earthquakes and Structures
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• 제19권4호
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• pp.227-241
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• 2020

An experimental study has been carried out to investigate the effect of beam to column connection rigidity on the behavior of infilled steel frames. Five half scale, single-story and single-bay specimens, including four infilled frames, as well as, one bare frame, were tested under in-plane lateral cyclic reversal loading. The connections of beam to column for bare frame as well as two infill specimens were rigid, whereas those of others were pinned. For each frame type, two different infill panels were considered: (1) masonry infill, (2) masonry infill strengthened with shotcrete. The experimental results show that the infilled frames with pinned connections have less stiffness, strength and potential of energy dissipation compared to those with rigid connections. Furthermore, the validity of analytical methods proposed in the literature was examined by comparing the experimental data with analytical ones. It is shown that the analytical methods overestimate the stiffness of infilled frame with pinned connections; however, the strength estimation of both infilled frames with rigid and pinned connections is acceptable.

• Steel and Composite Structures
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• 제13권5호
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• pp.409-421
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• 2012

Recently, as the height of building is getting higher, the applications of CFST column for high-rise buildings have been increased. In structural system of high-rise building, The RC core and exterior concrete-filled tubular (CFST) column-beam pinned connection is one of the structural systems that support lateral load. If this structural system is used, due to the minimal CFST column thickness compared to that of the CFST column width, the local moment occurred by the eccentric distance between the column flange surface from shear bolts joints degrades the shear strength of the CFST column-beam pinned connections. This study performed a finite element analysis to investigate the shear strength under eccentric moment of the CFST column-beam pinned connections. The column's width and thickness were used as variables for the analysis. To guarantee the reliability of the finite element analysis, an actual-size specimens were fabricated and tested. The yield line theory was used to formulate an shear strength formula for the CFT column-beam pinned connection. the shear strength formula was suggested through comparison on the results of FEM analysis, test and yield lime theory, the shear strength formula was suggested.

• 한국강구조학회 논문집
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• 제15권5호통권66호
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• pp.551-559
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• 2003

강골조의 보-기둥 접합부에 대한 해석과 설계는 일반적으로 완전한 강접이나 마찰이 없는 완전한 핀접합으로 가정하는 것이 보통이다. 이러한 경우, 구조해석 및 설계과정을 단순화시키는 장점은 있으나, 실제 철골 접합부에서는 작용하중에 대하여 어느 정도의 모멘트 전달과 회전구속력을 갖는 반강접으로 해석해야 하므로 실제와는 다소 차이가 날 수 있다. 이에, 본 연구에서는 고정계수에 의한 기둥-보 접합부의 반강접성과 P-delta효과를 고려한 골조의 비선형 해석 프로그램을 작성하고, 수치해석을 통해 평면 강골조의 변형과 내력에 미치는 접합강성의 영향을 검토하였으며, 상용의 해석프로그램인 MIdas Gen과 비교하였다.

• 한국강구조학회 논문집
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• 제8권3호통권28호
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• pp.127-137
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• 1996

Connections as basic elements and an integrated part of a steel frame has an effect on the frame's performance. Conventional analysis and design techniques are based on either idealized fixed or pinned conditions. In fact, the use of rigid or pinned connection model in steel frame analysis serves the purpose of simplifying the analysis and design processes, but all connections used in current pratice possess stiffness and transfer moment which fall between the extreme cases of fully rigid and ideally pinned. To predict the behavior of the semi-rigid steel frames, it is necessary to predict the moment-rotation behavior of the beam-to-column connections. In this research, prediction equation for moment-rotation behavior of the beam-to-column connection is suggested and the effect of design parameters has investigated. Prediction model, in a nondimensional form shows the moment-rotation characteristic for connections. It is composed of the curve fitting power function using standardization constant K and 4 parameter $KM_o$, ${\theta}_0$, b, n based on the pretest result about moment-rotation behavior of connection.

• Structural Engineering and Mechanics
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• 제68권5호
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• pp.591-601
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• 2018

Non-moment beam-to-column connections, which are usually referred to as simple or shear connections, are typically designed to carry only gravity loads in the form of vertical shears. Although in the analysis of structures these connections are usually assumed to be pinned, they may provide a small amount of rotational stiffness due to the typical connection details. This paper investigates the effects of this small rotational restraint of simple beam-to-column connections on the behavior and seismic response of steel braced non-moment resisting frames. Two types of commonly used simple connections with bolted angles, i.e., the Double Web angle Connection (DWC) and Unstiffened Seat angle Connection (USC) are considered for this purpose. In addition to the pinned condition - as a simplified representation of these connections - more accurate semi-rigid models are established and then applied to some frame models subjected to nonlinear pushover and nonlinear time history analyses. Although the use of bracing elements generally reduces the sensitivity of the global structural response to the behavior of connections, the obtained results indicate considerable effects on the local responses. Namely, our results show that consideration of the real behavior of connections is essential in designing the column elements where the pin-connection assumption significantly underestimates design of outer columns of upper stories.

• Structural Engineering and Mechanics
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• 제65권3호
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• pp.327-334
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• 2018

In the steel structures design, beam-to-column connections are usually considered either rigid or pinned, while their actual behavior lies between these two ideal cases. This consideration has a major influence on the results of the local and the global behavior of steel structures. This influence is noticed in the case of a static analysis, and has an important effect in the case of a dynamic analysis. In fact, pinned and rigid nodes can be considered as two specific cases of a semi-rigid behavior. To study the efficiency of the classification adopted in Eurocode 3, a numerical simulation of semi-rigid nodes has been carried out using the software ANSYS. In the aim to validate this simulation, the numerical results are compared to those of an analytical approach. After that, the validated numerical simulation has been used, to evaluate the efficiency of the classification adopted by the Eurocode 3, regarding semi-rigid connections. Finally, a new method is proposed to define a more accurate evaluation about semi-rigid connections.

• Steel and Composite Structures
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• 제1권1호
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• pp.1-16
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• 2001

Due to aesthetic, economic, and structural performance, the use of structural hollow sections as columns in both continuous moment resisting and nominally pinned construction is attractive. Connecting the beams to these sections is somewhat problematic as there is no access to the interior of the section to allow for the tightening of a standard bolt. Therefore, bolts that may be tightened from one side, i.e., blind bolts, have been developed to facilitate the use of site bolting for this arrangement. This paper critically reviews available information concerning blind bolting technology, especially the performance of fasteners in shear, tension, and moment resisting connections. Also provided is an explanation of the way in which the results have been incorporated into design guidance covering the particular case of nominally pinned connections. For moment resisting connections, it is concluded that whilst the principle has been adequately demonstrated, sufficient data are currently not available to permit the provision of authoritative design guidance. In addition, inherent flexibilities in the connections mean that performance equivalent to full strength and rigid is unlikely to be achievable: a semicontinuous approach to frame design will therefore be necessary.

• Earthquakes and Structures
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• 제16권4호
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• pp.469-485
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• 2019

A numerical investigation regarding local (${\mu}_L$) and story (${\mu}_S$) ductility demand evaluation of steel buildings with perimeter moment resisting frames (PMRF) and interior gravity frames (IGF), is conducted in this study. The interior connections are modeled, firstly as perfectly pinned (PP), and then as semi-rigid (SR). Three models used in the SAC steel project, representing steel buildings of low-, mid-, and high-rise, are considered. The story ductility reduction factor ($R_{{\mu}S}$) as well as the ratio ($Q_{GL}$) of $R_{{\mu}S}$ to ${\mu}_L$ are calculated. ${\mu}_L$ and ${\mu}_S$, and consequently structural damage, at the PMRF are significant reduced when the usually neglected effect of SR connections is considered; average reductions larger than 40% are observed implying that the behavior of the models with SR connections is superior and that the ductility detailing of the PMRF doesn't need to be so stringent when SR connections are considered. $R_{{\mu}S}$ is approximately constant through height for low-rise buildings, but for the others it tends to increase with the story number contradicting the same proportion reduction assumed in the Equivalent Static Lateral Method (ESLM). It is implicitly assumed in IBC Code that the overall ductility reduction factor for ductile moment resisting frames is about 4; the results of this study show that this value is non-conservative for low-rise buildings but conservative for mid- and high-rise buildings implying that the ESLM fails evaluating the inelastic interstory demands. If local ductility capacity is stated as the basis for design, a value of 0.4 for $Q_{GL}$ seems to be reasonable for low- and medium-rise buildings.

• 한국강구조학회 논문집
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• 제18권5호
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• pp.525-534
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• 2006

기둥과 보를 핀접합부로 연결하는 경우 볼트열과 기둥플랜지면 사이의 편심거리에 의해 강관면에 국부적인 모멘트가 유발 되어 기둥의 내력을 저하시킬 수 있다. 본 논문에서는 각형강관 기둥-보 핀접합부를 대상으로 유한요소해석 프로그램을 이용하여 기둥의 폭과 두께 변화, 내부보강 유무, 축력의 유무에 의한 변수로 모멘트에 의한 각형강관 기둥의 내력저하를 규명하기위해 해석을 수행 하였다. 유한요소해석결과에 대한 신뢰성을 확보하기 위해 일부 실험체를 제작하여 실험을 수행하였다. 각형강관 기둥-보 핀접합부의 내력식을 제안하기 위해 항복선 이론을 적용하였다. 그 결과 각형강관 기둥-보 편접합부의 모멘트에 의한 기둥의 내력은 폭과 두께의 증가에 따라 향상되었으며 기둥의 폭두께비가 동일하여도 기둥의 크기 증가로 내력이 향상되었다. 각형강관 기둥의 무보강형태에 대한 내력의 한계치를 제시 하였으며 한계치를 만족하지 못하는 경우 기둥 내부의 보강이 필수적이다. 따라서 각형강관 기둥의 내력 향상과 제작성을 고려하여 수평보강재 의 형태를 제안하였다. 최종적으로 모멘트에 의한 내력저하를 고려한 각형강관 기둥-보 핀접합부의 내력식을 무보강형태와 수평보강형태로 각각 제안하였다.

• Structural Engineering and Mechanics
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• 제31권3호
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• pp.315-331
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• 2009

Mechanical connections are recognized as extremely important elements in the aspect of strength and structural safety. However, classical structural model does not consider the connection stiffness properties, and are based on models with pinned or rigid joints only. In fact, mechanical connections are deformable and behave not linearly, affecting the whole structure and inducing nonlinear behavior as well. The quantification of this effect, however, depends on the description of the working of the connectors and the wood response under embedment. The theoretical modeling of wood structures with semi-rigid connections involves not only the structural analysis, but also the modeling of both single and grouped moment resisting connectors and the study of the wood properties under embedment. The proposal of this paper is to approach these aspects, and to quantitatively study the influence of the moment resistant connection in wooden framed structures. Comparisons between rigid and semi-rigid connections and between linear and nonlinear analysis lead to quantitative results.