• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.15 no.4
• /
• pp.715-725
• /
• 2002

In this study, a method to determine the deformed shape of planar cable under vertical loads was presented. To obtain the deformed shape of cable by general cable theorem, a sag at arbitrary point is usually given. However, in general cases without a given sag, the proposed method determines the deformed shape of cable based on the equations of cable theorem and geometric compatibility by iterative way. The method was also extended to slove extensible cable. It was acknowledged from numerical analysis and model tests in laboratory that the proposed method is valid lot analysis of extensible cable as well as unextensible cable.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2011.04a
• /
• pp.224-227
• /
• 2011

케이블구조의 기하학적 비선형해석을 위한 탄성포물선 케이블요소를 제시한다. 탄성현수선 케이블요소에 대한 적합조건과 접선강도행렬을 토대로 장력이 충분히 도입되어 자중에 의한 처짐 형상이 포물선에 가깝다는 가정 하에서 무응력길이를 포함하는 탄성포물선 케이블요소의 비선형 힘-변형관계식과 접선강도 행렬을 구한다. 또한 현(chord)방향으로 두 케이블요소의 등가 공칭장력식을 정의한다. 탄성포물선 케이블 요소의 수치적인 정확성을 확인하기 위하여, 경사진 케이블을 탄성현수선과 탄성포물선 케이블요소로 각각 모델링하여 매개변수 해석을 수행하고 비교, 분석한 결과를 제시한다.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.20 no.1
• /
• pp.1-7
• /
• 2007

This study introduces an elastic parabolic cable element for initial shaping analysis of cable-stayed bridges. First, an elastic catenary cable theory is shortly summarized by deriving the compatibility condition and the tangent stiffness matrices of the elastic catenary cable element. Next, the force-deformation relations and the tangent stiffness matrices of the elastic parabolic cable elements are derived from the assumption that sag configuration under self-weights is small. In addition the equivalent cable tension is defined in the chord-wise direction. Finally, to confirm the accuracy of this element, initial shaping analysis of cable-stayed bridges under dead loads is executed using TCUD in which stay cables are modeled by an elastic parabolic cable and an elastic catenary cable element, respectively. Resultantly it turns that unstrained lengths of stay cables, the equivalent cable tensions, and maximum tensions by the parabolic cable element are nearly the same as those by the catenary cable elements.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.24 no.1
• /
• pp.87-95
• /
• 2011

A rational method for determination of initial cable forces in cable-stayed bridges without complicated nonlinear analysis is presented. Initial shape analysis for cable-stayed bridges should be able to find optimizated initial cable forces and unstrained length that minimize deflection and vending moments of the deck and pylon. A presented method utilizing the idea of force equilibrium organizes initial shape analysis for each types of cable-stayed bridges. The results of that analysis were compared to several existing methods for 2D numerical examples. And for 3D actual bridges, the improved TCUD method was performed to demonstrate the accuracy of this study.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.3 no.1
• /
• pp.16-20
• /
• 2012

During construction of the cable-stayed bridge, not only shape of deck and pylon but also cable forces are main factors for geometry control. Especially, geometry control of deck must be controlled for adjusting design value of vertical and lateral alignment as well as closing of key segment. Also, both the deck level error and cable force error occur necessarily during the construction stage in cable stayed bridge. The errors are caused by different of material properties and computer modeling, and construction mistake, and so on. These causes bring about that the forces of cable and the displacement of deck show different tendency from the theoretical values. Therefore, these errors must necessarily be adjusted and can be improved through adjustment of cable length. In this study, a new optimization tool is proposed to adjust the errors of the second Dolsan cable-stayed bridge.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.5A
• /
• pp.361-367
• /
• 2011

This study introduces an elastic parabolic cable element for initial shaping analysis of cable-supported structures. First, an elastic catenary cable theory is shortly summarized by deriving the compatibility condition and the tangent stiffness matrices of the elastic catenary cable element. Next, the force-deformation relations and the tangent stiffness matrices of the elastic parabolic cable elements are derived and discussed under the assumption that sag configuration under self-weights is small. In addition the equivalent cable tension is defined in the chord-wise direction. Finally, to demonstrate the accuracy of the elastic parabolic cable element, nonlinear relationships of nominal cable tension-chord length and nominal cable tension-tangential stiffness for a single element are presented and compared with results using an elastic catenary cable theory as the slope is varied.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.25 no.1
• /
• pp.101-108
• /
• 2012

Initial shape analysis for cable-stayed bridges should be able to find optimizated initial cable forces and unstrained length that minimize deflection and bending moments of the deck and pylon. Comparison study of an improved initial force method and TCUD method for determination of initial cable forces in cable-stayed bridges is presented in this paper. For this purpose, an elastic catenary cable element and a nonlinear frame element are firstly described. And concepts and algorithm of two analysis methods are then presented. Finally to demonstrate the validity and the accuracy of two methods, numerical examples for initial state problems of cable-stayed bridges are given and compared based on these methods.

• Journal of Korean Society of Steel Construction
• /
• v.9 no.4 s.33
• /
• pp.579-588
• /
• 1997

During the construction of cable stayed bridge, errors are always caused by various reasons, accumulated and amplified through the complex construction steps. It is likely that the undesirable stress distribution of members and the large deflection of the bridge different from design values come out The adjustment of cables during construction is absolutely indispensable to correct the stress distribution of the members and the geometrical configuration of the bridge. In the conventional method, weight coefficients are used to consider the difference of units between cable forces and girder deflections during the optimization process of cable adjustment. However, it is not easy to determine weight coefficients and the adjustment must be repeated several times with the time consuming process of the determination of new weight coefficients in case that errors are out of design allowable limits. In this paper, fuzzy linear regression analysis is applied to the cable adjustment to overcome those problems. In the application of fuzzy linear regression analysis method the designer's intention and the design allowable limits can be formulated in the form of the constraints of the linear optimization problem. Therefore, the cable adjustment in construction site can be carried out with the fuzzy linear regression analysis more rapidly than with the convetional method.