• Title/Summary/Keyword: beam-column effect

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Effect of Geometric Shapes on Stability of Steel Cable-stayed Bridges (기하형상에 따른 강사장교의 안정성에 관한 연구)

  • Kim, Seung-Jun;Han, Seung-Ryong;Kim, Jong-Min;Cho, Sun-Kyu;Kang, Young-Jong
    • Journal of Korean Society of Steel Construction
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    • v.23 no.1
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    • pp.13-27
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    • 2011
  • This paper presents an investigation of the structural stability of cable-stayed bridges, using geometric nonlinear finite-element analysis and considering various geometric nonlinearities, such as the sag effect of the cables, the beam-column effect of the girder and mast, and the large displacement effect. In this analytic research, a nonlinear frame element and a nonlinear equivalent truss element were used to model the girder, mast, and cable member. The live-load cases that were considered in this research were assumed based on the traffic loads. To perform reasonable analytic research, initial shape analyses in the dead-load case were performed before live-load analysis. In this study, the geometric nonlinear responses of the cable-stayed bridges with different cable arrangement types were compared. After that, parametric studies on the characteristics of the structural stability in critical live-load cases were performed considering various geometric parameters, such as the cable arrangement type, the stiffness ratios of the girder and mast, the area of the cables, and the number of cables. Through this parametric study, the effect of geometric shapes on the structural stability of cable-stayed bridges was investigated.

Analytical Study of Geometric Nonlinear Behavior of Cable-stayed Bridges (사장교의 기하학적 비선형 거동의 해석적 연구)

  • Kim, Seungjun;Lee, Kee Sei;Kim, Kyung Sik;Kang, Young Jong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.1A
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    • pp.1-13
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    • 2010
  • This paper presents an investigation on the geometric nonlinear behavior of cable-stayed bridges using geometric nonlinear finite element analysis method. The girder and mast in cable-stayed bridges show the combined axial load and bending moment interaction due to horizontal and vertical forces of inclined cable. So these members are considered as beam-column member. In this study, the nonlinear finite element analysis method is used to resolve the geometric nonlinear behavior of cable-stayed bridges in consideration of beam-column effect, large displacement effect (known as P-${\delta}$ effect) and cable sag effect. To analyze a cable-stayed bridge model, nonlinear 6-degree of freedom frame element and nonlinear 3-degree of freedom equivalent truss element is used. To resolve the geometric nonlinear behavior for various live load cases, the initial shape analysis is performed for considering dead load before live load analysis. Then the geometric nonlinear analysis for each live load case is performed. The deformed shapes of each model, load-displacement curves of each point and load-tensile force curves for each cable are presented for quantitative study of geometric nonlinear behavior of cable-stayed bridges.

Reinforcement of shield tunnel diverged section with longitudinal member stiffness effect (종방향 부재의 강성효과를 고려한 쉴드 터널 분기부 보강 및 해석기법)

  • Lee, Gyu-Phil;Kim, Do
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.5
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    • pp.675-687
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    • 2019
  • In recent years, the needs for double deck-tunnels have increased in large cities due to the increase in traffic volume and high land compensation costs. In Korea, a network type tunnel which is smaller than general road tunnels and crosses another tunnel underground is planned. In the shield tunnel joints between the existing shield tunnel and the box-type enlargement section, a partial steel-concrete joint is proposed where the bending moment is large instead of the existing full-section steel joint. In order to analysis the enlargement section of the shield tunnel diverged section to reflect the three-dimensional effect, the two-dimensional analysis model is considered to consider the column effect and the stiffness effect of the longitudinal member. A two-dimensional analysis method is proposed to reflect the stiffness of the longitudinal member and the column effect of the longitudinal point by considering the rigidity of the longitudinal member as the elastic spring point of the connecting part in the lateral model. As a result of the analysis of the model using the longitudinal member, it was considered that the structural safety of the partial steel-concrete joint can be secured by reducing the bending moment of the joint and the box member by introducing the longitudinal member having the stiffness equal to or greater than a certain value.

Effects of Geometric Characteristics on the Ultimate Behavior of Steel Cable-stayed Bridges (기하학적 특성이 강사장교의 극한 거동에 미치는 영향)

  • Kim, Seungjun;Shin, Do Hyoung;Choi, Byung Ho;Kang, Young Jong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.6A
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    • pp.327-336
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    • 2012
  • This study presents the effects of various geometric properties on the ultimate behavior of steel cable-stayed bridges. In general, cable-stayed bridges are well known as a very efficient structural system, because of those geometric characteristics, but at the same time, the structure also shows complex structural behavior including various nonlinearities which significantly affect to the ultimate behavior of the structure. In this study, the effects of various geometric properties of main members on the ultimate behavior under specific live load cases, which had been studied in previous studies, were investigated using a rational analytical method. In this parametric study, sectional dimensions of main members were considered as main geometric parameters. For the rational ultimate analysis under specific live load cases, the 2-step analysis method, which contains initial shape analysis and live load analysis, was used. As the analysis model, 920.0 m long steel cable-stayed bridges were used and two different types of cable arrangement were considered to study the effect of the cable arrangement types. Through this study, the effects of various geometric properties on the characteristics of the ultimate behavior of steel cable-stayed bridges were intensively investigated.

Stability Analysis of Steel Cable-stayed Bridges under Construction Stage (폐합 전 강사장교의 안정성 해석)

  • Kim, Seung-Jun;Shim, Kyung-Suk;Won, Deok-Hee;Cho, Sun-Kyu;Kang, Young-Jong
    • Journal of Korean Society of Steel Construction
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    • v.23 no.1
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    • pp.99-111
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    • 2011
  • This paper presents an investigation of the structural stability of cable-stayed bridges in the construction stage, using geometric nonlinear finite-element analysis and considering various geometric nonlinearities, such as the sag effect of the cables, the P-${\Delta}$ effects of the girder and mast, and the large displacement effect. Initial shape analysis and construction-stage analysis were performed to determine the equilibrium of the structure in the construction stage. After that, geometric nonlinear analysis was performed to study structural stability. In this study, the weight of the derrick crane and the key segment were considered the main external loads, which were applied to the tip of the center span. The cable arrangement type and the stiffness ratios of the girder and mast were considered the main parameters of the analytic research. Based on the results of the analysis, the change in the buckling mode and critical load factors with respect to the cable arrangement type and the stiffness ratios of the girder and mast was investigated. The buckling modes of the steel cable-stayed bridges in the construction stage were classified, and the ranges of the stiffness ratios of the girder and mast, which show these classified buckling modes, were suggested.

Analytical Study of Ultimate Behavior of Steel Cable-stayed Bridges (완성계 강사장교의 극한 거동의 해석적 연구)

  • Kim, Seungjun;Im, Seok-Been;Lee, Kee-Sei;Kang, Young-Jong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.2A
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    • pp.85-95
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    • 2012
  • This paper presents an investigation on the ultimate behavior of steel cable-stayed bridges using nonlinear finite element analysis method. Cable-stayed bridges exhibit various geometric nonlinearities as well as material nonlinearities, so rational nonlinear finite element analysis should be performed for investigation of the ultimate behavior. In this study, ultimate behavior of steel cable-stayed bridges was studied using rational ultimate analysis method. Nonlinear equivalent truss element and nonlinear frame element were used for modeling the cable, girder and mast. Moreover, refined plastic hinge method was adopted for considering the material nonlinearity of steel members. In this study, the 2-step analysis method was used. Before live load analysis, initial shape analysis was performed in order to consider the dead load condition. For investigation of the ultimate behavior of steel cable-stayed bridges, analysis models which span length is 920.0 m were used. Radiating type and fan type were considered as the cable-arrangement types. With various quantitative evidences such as load-displacement curves, deformed shapes, locations of the yield point or region, bending moment distribution and so on, the ultimate behavior of steel cable-stayed bridges was investigated and described in this paper.