Analysis Of Cable-stayed Bridges Research Articles

Equivalent Plane Algorithm for Static Analysis of Cable-Stayed Bridge with Spatial Cables

Equivalent Plane Algorithm for Static Analysis of Cable-Stayed Bridge with Spatial Cables

The behavior of reinforced concrete pylons in the static analysis of cable-stayed bridges

In this paper, we consider a linear static analysis of cable-stayed bridges with different pylon shapes under their own weight. The cable-stayed bridge is one of the modern bridges that are built to cover large spans. It is therefore necessary to study the behavior of the pylons before you can apply it in practice. For this study, different pylon shapes are compared with the size of the bridge span, while other parameters remain unchanged. The various forms of pylons considered for a cable-stayed bridge are diamond, small diamond, Y-inverted, A, H and U-shaped. The height of the pylon remains the same for all cable-stayed bridge models with different pylon shapes. The bridge simulation was prepared using the Midas/Civil software. For this study, the semi-fan type cable-stayed bridge was adopted. The study gives the deformed state of the pylons, i.e. bending moments, transverse and longitudinal forces, and deflections. This study will be useful for selecting the shape of the pylon for the bridge used in specific conditions.

Spatial combined cable element for cable-supported bridges

Purpose The purpose of this paper is to analyze the cable-supported bridges more efficiently by building the finite element model with the spatial combined cable element. Design/methodology/approach The spatial combined cable element with rigid arms and elastic segments was derived. By using the analytical solution of the elastic catenary to establish the flexibility matrix at the end of the cable segment and adding it to the flexibility matrix at the ends of the two elastic segments, the flexibility matrix at the end of the cable body is obtained. Then the stiffness matrix of the cable body is established and the end force vector of cable body is given. Using the displacement transformation relationship between the two ends of the rigid arm, the stiffness matrix of the combined cable element is derived. By assigning zero to the length of the elastic segment(s) or/and the rigid arm(s), many subdivisions of the combined cable element can be obtained, even the elastic catenary element. Findings The examples in this field and specially designed examples proved the correctness of the proposed spatial combined cable element. Originality/value The combined cable element proposed in this study can be used for the design and analysis of cable-stayed bridges. Case studies show that it is able to simulate cable accurately and could also be used to simulate the suspenders in arch bridges as well in suspension bridges.

A simplified method for free vibration analysis of cable-stayed bridges

A simplified method for the accurate prediction of the natural frequencies of cable-stayed bridges is proposed in this paper. In the proposed method artificial neural network (ANN) is applied to derive a simple formula to predict the natural frequencies of cable-stayed bridges based on existing natural frequency data. Unlike in the existing empirical methods, no functional relationship among the variables is assumed before we can develop an ANN model. ANN automatically constructs the relationships and adapts based on the training data presented to them. Also, the proposed method takes into account the wide range of parameters which may have a significant effect on the natural frequencies of cable-stayed bridges. The proposed method is particularly useful for the preliminary design stage of cable-stayed bridges where free vibration analysis needs to be carried out. The proposed method is compared with two existing empirical methods. It is found that the simplified method proposed in this study can produce a more accurate prediction of the natural frequencies of cable-stayed bridges than the existing empirical methods.

Nonlinear Seismic Response Analysis of Cable-Stayed Bridge under Uniform and Traveling-Wave Excitations

The finite element method model of a 670.56m span cable-stayed bridge was established and the dynamic characteristic and nonlinear earthquake-responses of it under uniform and traveling-wave excitations were systematic studied. Results show that: 1) its former 10 rank frequency are located very dense which shows that more modes shape should be considered when dealing with the dynamic analysis. 2) The traveling-wave excitation has greater effect on long-span cable-stayed bridge, especially on the more flexible component and great attention should be paid to the design of such kind of bridge.

Optimization of Pre-Tensioning Cable Forces in Highly Redundant Cable-Stayed Bridges

Cable-stayed bridges have been developing rapidly in the last decade and have become one of the most popular types of long-span bridges. One of the important issues in the design and analysis of cable-stayed bridges is determining the pre-tensioning cable forces that optimize the structural performance of the bridge. Appropriate pre-tensioning cable forces improve the damaging effect of unbalanced loading due to the deck dead load. Because the cable-stayed structure is a highly undetermined system, there is no unique solution for directly calculating the initial cable forces. Numerous studies have been conducted on the specification of cable pre-tensioning forces for cable-stayed bridges. However, most of the proposed methods are limited in their ability to optimize the structural performance. This paper presents an effective multi-constraint optimization strategy for cable-stayed bridges based on the application of an inverse problem through unit load method (ULM). The proposed method results in less stresses in the bridge members, more stability and a shorter simulation time than the existing approaches. The finite element (FE) model of the Tatara Bridge in Japan is considered in this study. The results show that the proposed method successfully restricts the pylon displacement and establishes a uniform deck moment distribution in the simulated cable-stayed bridge; thus, it might be a useful tool for designing other long-span cable-stayed bridges.

Nonlinear Analysis of Cable-Stayed Bridge

The nonlinear basic theory and nonlinear influence factor of cable-stayed bridge has been introduced. Quantitative analysis to the sag effect, beam-column effect and large deformation effect has been done based on a cable-stayed bridge. Analysis show that the sag effect, beam-column effect and large deformation effect of cable force is not obvious, but the sag effect should not been ignored in the calculation of the main beam.

Three-Dimensional Geometric Nonlinear Analysis of Composite Cable-Stayed Bridges Using a Refined Double-Beam Model

In this paper, a refined double-beam finite-element model is constructed for composite cable-stayed bridges. Using this refined model, the authors aimed at performing more accurate three-dimensional (3D) analyses of cable-stayed bridges by considering all the geometric nonlinearities, including large 3D rotation issues, using catenary cable elements for cables, and taking into account member eccentricities between cable anchor points with the deck and member neutral axes. To consider member eccentricities and avoid using rigid links to connect the eccentricities, a validated two-step procedure is developed to transfer member forces and stiffness from the fluctuating neutral axis lines to a straight reference line. Through a numerical example, the effect of member eccentricity is discussed, and it is clearly shown that member eccentricity has a larger influence on displacements and bending moments than on modal responses. Through a detailed comparison example with previous research and existing software, the refined model presented in this paper demonstrates higher accuracy.

Finite Element Modal Analysis of the Cable-Stayed Bridge

In the process of modeling, ignoring the displacement of the pier directly replaced with fixed constraint, beam elements were adopted to simulate girder and pylon, and link elements were adopted to simulate the cable. The first ten order natural vibration mode and natural frequency were obtained, and the dynamic characteristics analysis of a single pylon cable-stayed bridge was discussed, which can provide certain reference and guidance for solving the problem of the cable-stayed bridge design.

Aerodynamic Forces of Stay Cables Incorporating in Flutier Analysis

With the length of stay cables close to 580m, only inclusion in aerodynamic forces of main deck cannot reflect the actual situation during wind-resistant design. The aerodynamic forces of stay cables should be considered in the three-dimensional flutter analysis of cable-stayed bridges. In this paper, mathematic expressions of unsteady aerodynamic force of stay cable were then derived in terms of aerodynamic damping and stiffness matrices. The above procedure is implemented into NACS by an independent module. As an example, the multimode flutter analysis of Sutong Bridge was conducted by using NACS. Fair agreement is achieved between the present numerical simulation and wind tunnel test results.

Seismic Response Analysis of Long Span Cable-Stayed Bridge under Non-Uniform Excitation

In this paper, non-uniform dynamic analysis of a cable-stayed bridge is carried out using the large mass method. The Ed Yangtze River highway bridge, constructed in Hubei province, is chosen as a numerical example. In the non-uniform dynamic analysis, various wave velocities are used for the travelling ground motion. Displacements and internal forces solutions obtained for the spatially varying ground motions are compared with those of the uniform excitation. It is observed that the velocity of the ground motion greatly influences the response of the bridge and the variability of the ground motions should be included in the time-history analysis of cable-stayed bridges.

Aerodynamic Analysis in Time Domain of a Cable-Stayed Bridge

To determine its actual dynamic responses under the wind loads, modal identification from the field tests was carried out for the Kao Ping Hsi cable-stayed bridge in southern Taiwan. The rational finite element model has been established for the bridge. With the refined finite element model, a nonlinear analysis in time domain is employed to determine the buffeting response of the bridge. Through validation of the results against those obtained by the frequency domain approach, it is confirmed that the time domain approach adopted herein is applicable for the buffeting analysis of cable-stayed bridges.

Structural Analysis of the Cantilever Construction Process in Cable-Stayed Bridges

This work deals with the analysis of cable-stayed bridges at different erection stages during construction, assuming the full or the partial cantilever method and performing multiple finite element computational procedure. The forward process and the backward process analysis are investigated and compared: the former is performed by following the sequence of erection stages in bridge construction and the latter is carried out in the reverse direction of erection procedures. The required pretension in cable-stays and the corresponding structural configurations of the bridge at different erection stages have been examined and compared in details, also by comparing either the linear computation procedure or the nonlinear computation procedure. Numerical, analytical and construction process results are presented, compared and commented upon.

Seismic Response Analysis of Cable-Stayed Bridges

For floating system cable-stayed bridge, the longitudinal displacement of stiffening girder and moments of towers are very large when strong earthquake happens. Too large displacement of stiffening girder leads to collision between girders of the main bridge and the approaches. Using spatial finite element model and time history analysis method, the seismic responses of cable-stayed bridge are studied considering the elasto-plastic effects. The results show that the displacement of stiffening girder is very large when no seismic reduction measures are adopted. The viscous dampers installed between the stiffening girder and towers can efficiently reduce seismic responses of the cable-stayed bridge. Especially, the displacement of stiffening girder can be controlled well to meet the design requirement. Using the optimum parameters of damper, the height of pier under tower and intermediate supports in side span on seismic responses are studied in detail. The longitudinal displacement of stiffening girder increases with the pier height increasing. The intermediate supports in side span are benefit for seismic reduction.

Seismic Response Analysis of Cable-Stayed Bridges

Seismic Response Analysis of Cable-Stayed Bridges

Bifurcation analysis of a parametrically excited inclined cable close to two-to-one internal resonance

This paper presents a study of how different vibration modes contribute to the dynamics of an inclined cable that is parametrically excited close to a 2:1 internal resonance. The behaviour of inclined cables is important for design and analysis of cable-stayed bridges. In this work the cable vibrations are modelled by a four-mode model. This type of model has been used previously to study the onset of cable sway motion caused by internal resonances which occur due to the nonlinear modal coupling terms. A bifurcation study is carried out with numerical continuation techniques applied to the scaled and averaged modal equations. As part of this analysis, the amplitudes of the cable vibration response to support inputs is computed. These theoretical results are compared with experimental measurements taken from a 5.4 m long inclined cable with a vertical support input at the lower end. In general this comparison shows a very high level of agreement.

Analysis of Cable-Stayed Bridge for APDL-Based Optimization

Optimum design for a cable-stayed bridge structure is very complicated because of large number of design variables. Use of ANSYS parametric design language in optimizing such structure consumes little computational time. The finished dead state analysis for single pylon double cable plane cable-stayed bridge with 120m long is performed. Mechanics equivalent are developed for the main pylon with concrete-filled steel tube. Prestress girder finite element model is established also. The theory of minimum bending strain energy is used in deriving the objective function as the quadratic form of the post-tensioning cable forces. In addition, the maximum deflection of the pylon and the maximum stresses of the main girder are both implemented in the optimization model. Optimized cable forces are found by optimization. Calculated results show that after the optimization, the cable force slightly changes, yet the internal force state under dead load remarkably improves, the bending stress of girder as well as the deflection of pylon significantly decreases. All these variations are satisfied for the limit value of engineering code. The results obtained revealed that the method presented indeed leads to optimal structural performance for the cable-stayed bridge in particular, and might be a useful reference for the design of other similar bridges.

Seismic Response Analysis of Cable-Stayed Bridge Considering Pile-Soil Dynamic Interaction

The large-span bridges always employ high-pile foundations, and its seismic response will take an important responsibility to affect the dynamic characteristics of whole bridge. In order to understand the effect of pile-soil dynamic interaction on dynamic characteristics and plastic development of the whole cable-stayed bridge system, the elasto-plastic seismic response of an actual cable-stayed bridge engineering considering material nonlinear was analyzed. And for reflecting the effect of pile-soil interaction, there were two modals applying to calculation. The results show that after considering pile-soil interaction, the structural actual dynamic characteristics can be more accurately reflected; pile-soil interaction performs a great influence on bending moment and shearing force of main girder and tower and the development of plastic zone get decrease. Meanwhile, Seismic wave chosen can greatly affect the response of structure. It will provide a basis for ensuring the ductility of structure and improving the seismic performance of structure.

Dynamic characteristics of cable vibrations in a steel cable-stayed bridge using nonlinear enhanced MECS approach

This paper focuses on the nonlinear vibrations of stay cables and evaluates the dynamic characteristics of stay cables by using the nonlinear enhanced MECS approach and the approximate approach. The nonlinear enhanced MECS approach is that both the girder-tower vibrations and the cable vibrations including parametric cable vibrations are simultaneously considered in the numerical analysis of cable-stayed bridges. Cable finite element method is used to simulate the responses including the parametric vibrations of stay cables. The approximate approach is based on the assumption that cable vibrations have a small effect on girder-tower vibrations, and analyzes the local cable vibrations after obtaining the girder-tower responses. Under the periodic excitations or the moderate ground motion, the differences of the responses of stay cables between these two approaches are evaluated in detail. The effect of cable vibrations on the girder and towers are also discussed. As a result, the dynamic characteristics of the parametric vibrations in stay cables can be evaluated by using the approximate approach or the nonlinear enhanced MECS approach. Since the different axial force fluctuant of stay cables in both ends of one girder causes the difference response values between two approach, it had better use the nonlinear enhanced MECS approach to perform the dynamic analyses of cable-stayed bridges.

Serviceability reliability analysis of cable-stayed bridges

A reliability analysis method is proposed in this paper through a combination of the advantages of the response surface method (RSM), finite element method (FEM), first order reliability method (FORM) and the importance sampling updating method. The accuracy and efficiency of the method is demonstrated through several numerical examples. Then the method is used to estimate the serviceability reliability of cable-stayed bridges. Effects of geometric nonlinearity, randomness in loading, material, and geometry are considered. The example cable-stayed bridge is the Second Nanjing Bridge with a main span length of 628 m built in China. The results show that the cable sag that is part of the geometric nonlinearities of cable-stayed bridges has a major effect on the reliability of cable-stayed bridge. Finally, the most influential random variables on the reliability of cable-stayed bridges are identified by using a sensitivity analysis.