• Journal of Korean Society of Steel Construction
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• v.29 no.1
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• pp.13-24
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• 2017

System buckling analysis is usually used to determine the critical buckling load in the buckling design of cable-stayed bridges. However, system buckling analysis may yield unexpectedly large effective lengths of the members subjected to a relatively small axial force. This paper proposes a new method to determine reasonable effective lengths of girder and tower members in steel cable-stayed bridges using fictitious axial forces. An improved inelastic buckling analysis with modified tangent modulus is also presented. The effective lengths of members in example bridges calculated using the proposed method are compared with those obtained using the conventional buckling analysis method. The proposed method provides much more resonable effective lengths of the members. When girder and tower members are built with HSB800 steel instead of conventional steel, the effective lengths of the members under a small axial force slightly decreases in the inelastic buckling analysis without fictitious axial forces, while the proposed method that considers fictitious axial forces provides almost no changes in such lengths.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1992.10a
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• pp.409-502
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• 1992

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.435-436
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• 2010

This research presents two important factors; first, the advanced design equation of effective bonding length at the interface between concrete and FRP materials is proposed when different bonding materials are applied and secondly maximum bonding strength between concrete-FRP bonding surface is evaluated under Freeze-thaw cycles.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.219-226
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• 2003

보 유사법을 이용하여 연속 압축재의 유효길이 계수를 각 경간별로 결정하는 방법을 제안한다. 제안하는 보 유사법은 4가지 단계로 요약할수 있는데 그 첫 단계는 주어진 압축재를 이것과 동일한 단면성능 및 경간을 갖는 연속보로 치환하는 것이다. 제 2단계에서는 연속보 각 경간의 중앙에 가상 집중 횡하중을 작용시킨 후 이로 인한 지점들에서의 재단 moment를 계산한다. 이때 각 경간중앙의 가상 집중 횡하중 방향은 좌굴 mode를 고려하여 교호로 바뀌도록 한다. 제 3단계에서는 또 하나의 제안식과 재단 모멘트를 이용하여 Kinney의 부분 고정도를 결정한다. 최종단계에서는 부분 고정도를 이용하여 유효길이를 각 경간별로 산정 한다. 제안한 방법은 다 경간 압축재에서 어느 경간이 맨 먼저 좌굴을 일으키는지 또한 이때의 임계하중은 어떤 값을 갖는지를 예측하게 한다.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.433-435
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• 2008

본 연구에서는 MR 유체를 특징으로 하는 대시포트형 마운트를 제안하고, 자극 형상의 변화가 MR유체 마운트의 감쇠력에 미치는 영향에 대하여 고찰하였다. 제안된 MR유체 마운트의 코어부에 발생하는 자기 특성에 대하여 살펴보기 위하여 자극(Magnetic pole)의 유효길이와 코어 중심부의 구조를 달리하여 대시포트를 제작하였다. 등가자기회로를 이용한 대략적인 계산방법에 의한 결과 자극의 유효길이가 증가할수록 자기저항은 감소하는 경향을 나타내지만, 그 밖의 설계인자들의 영향은 작게 나타났다. 상용해석프로그램을 이용하여 등가자기회로 결과와 비교를 하였으며, 대시포트 마운트를 제작하여 자극의 유효길이 변화에 대한 감쇠력의 변화를 실험적으로 비교하였다.

• Journal of Korean Society of Steel Construction
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• v.16 no.3 s.70
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• pp.355-363
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• 2004

In order to obtain the effective length factor of beam-column members of plane frames, this paper extensively used an alignment chart approach, based on the nomograph given in LRFD-AISC specification commentaries. However, it should be noted that various simplifications and assumptions were introduced in constructing the alignment chart. To overcome the practical limitations of the alignment chart, this paper proposes a simple but accurate procedure that determined the effective buckling length for stability design of main members of cable-supported bridges. This method requires the full system buckling analysis. The numerical examples showing the suitability of the present scheme are discussed and some conclusions are drawn.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.661-671
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• 2018

Domestic studies on steel plate concrete structures have focused on nuclear structures with high strength. In this study, the SC structure was applied to the general structure, and the SC structure that is advantageous in terms of safety and construction was limited to a special structure. As a basic study for applying SC, this paper proposes basic design information of a SC structure applying cement concrete to plan the structure, which is suitable for eco - friendliness by replacing concrete cement, an important factor in a SC structure, with blast furnace slag. This study examined the compression characteristics and the effective length factor under central compression load. To calculate the effective length factor, the Euler column theory was applied without applying plate theory. The effective length factor was calculated from the yield strength of the steel plate, buckling of the steel plate, and the point at which the concrete was broken. In addition, this study examined whether the maximum compressive strength meets the national and international reference equations with the slenderness ratio (B/t) as a parameter. By analyzing the buckling of the specimen by applying the column theory and selecting the strain of the measured steel plate, the effective length factor was analyzed and compared with the value presented in the reference equation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.247-255
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• 2022

In this paper, a bending test was conducted on beams with two lap splice details when the effective depth of tensile high strength headed bars overlapped is the same and different. Through bending test, the lap splice performance of the high-strength headed bars was evaluated, and the applicability of the KDS-2021 design formula was evaluated. In the LS specimens with lap splice details where the high strength bars had the same effective depth, all specimens with 1.3 times or more of the development length of the KDS-2021 equation and 1 times or more of the ACI318-19 had the flexural failure mode after the ductile behavior to ensure sufficient lap splice performance. For specimens with details of lap joints between headed bars with different effective depth, when lap splice length is calculated by the KDS-2021 formula, the flexural stress may be transmitted so that the flexural strength at the cross section with the large effective depth and the cross section with the small effective depth becomes similar.

• Journal of the Korean GEO-environmental Society
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• v.10 no.1
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• pp.5-14
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• 2009

This study is to analyze numerically the spatial behaviors of the solute transport in a spatially correlated variable-aperture fracture under the effective normal stress conditions. Numerical results show that the solute transport in a fracture is strongly affected by the spatial correlation length of apertures and applied effective normal stress. According to increasing spatial correlation length, the mean residence time of solute is decreased and the tortuosity and Peclet number (is a dimensionless number relating the rate of advection of a flow to its rate of diffusion) is also decreased. These results mean that the geometry of the aperture distribution is favorable to the solute transport as the spatial correlation length is increased. However, according to the applied effective normal stress is increased, the mean residence time and tortuosity have a tendency to increase but the Peclet number is decreased. The main reason that the Peclet number is decreased, is that the solute is displaced by one or two channels with relatively higher local flow rate due to the increment of contact areas by increasing effective normal stress. Moreover, based on numerical results of the solute transport in this study, the exponential-type correlation formulae between the mean residence time and the effective normal stress are proposed.

• Ecology and Resilient Infrastructure
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• v.4 no.4
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• pp.245-254
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• 2017

In this study, the flow characteristics and bed changes in the upstream and downstream of weirs with the variation of the weir angels are investigated quantitatively through the laboratory experiments. As the angle of weir increases, the effective weir length decreases. Delta is developed by the sediments inflow upstream and migrates downstream. Delta migration speed decreases as it approaches to the weir upstream, and the size is getting big. As the dimensionless weir length increases, the dimensionless wave length decreases at the downstream of the weir. However, the dimensionless bar height decreases. The dimensionless wavelength increases with the bar height downstream from the weir.