Analysis Of Long-span Cable-stayed Bridges Research Articles

A Simple Analytical Approach to the Aeroelastic Stability Problem of Long-Span Cable-Stayed Bridges

This paper deals with the aeroelastic stability problem of long-span cable-stayed bridges under an approaching crosswind flow. Starting from a continuous model of the fan-shaped bridge scheme with both H- or A-shaped towers, critical states of the coupled wind-structure system are identified by means of a variational formulation, accounting for torsional and flexural (vertical and lateral) bridge oscillations. The overall bridge dynamics is described by introducing simple mechanical systems with equivalent stiffness properties and, under the assumption of a prevailing truss-like bridge behavior, analytical estimates for dominant stiffness contributions are proposed. Several case studies are discussed and comparisons with experimental evidences as well as with available analytical and numerical results are presented. The proposed simplified approach proves to be consistent and effective for successfully capturing the main wind-bridge interaction mechanisms, and it could be considered as a useful engineering tool for the aeroelastic stability analysis of long-span cable-stayed bridges.

A quasi-secant continuous model for the analysis of long-span cable-stayed bridges

In this paper a non-linear continuous model for the statical analysis of long-span cable-stayed bridges with fan scheme and H-shaped towers is proposed. This model is based on a quasi-secant large-displacement formulation of the stays-deck interaction and involves an Euler-Bernoulli/De Saint Venant model for the girder. An approximate closed-form solution of the statical problem, in which flexural and torsional terms are coupled, is obtained by means of a perturbative technique and according to the prevailing “truss-like” structural behavior. Results for some study-cases are compared with those relevant to both classical models and numerical solutions, proving effectiveness and applicability of the proposed model.

GPS dynamic monitoring experiment and result analysis of long-span cable-stayed bridge

For the sake of timely appraising the working condition of the bridge, measuring the dynamic characteristics of the bridge structure is very important and necessary. A GPS dynamic monitoring test was carred out in the Wuhan Baishazhou Bridge, which is one of the longest span cable-stayed bridges having been built in China. This paper introduces the experimental implementing scheme and data processing method. The vibration characteristics of the middle span of cable-stayed bridge are availably obtained by use of the spectral analytic approach. The measuring results are very identical to the theoretical designed values. The research demonstrates that, with GPS receiver of the high sampling rate and suitable data processing method, the vibration characteristics of the bridge structure can be determined with high accuracy.

Efficient methods for elsto-plastic finite displacement analysis of long-span cable-stayed bridges

Efficient methods for elsto-plastic finite displacement analysis of long-span cable-stayed bridges

Improved finite strip method for nonlinear analysis of long-span cable-stayed bridges

As the spans of cable-stayed bridges increase, the degree of nonlinearity of structural response increases markedly. For future spans greater than (say) 800 m, existing three-dimensional software then becomes very time consuming and costly, and a finite strip approach becomes more attractive and preferable. An improved finite strip method using two types of longitudinal shape functions is developed in this paper for the analysis of girders of such bridges. The nonlinearities due to sag and angle change of the cables are taken into account by means of catenary theory. The substructuring technique and the modified Newton–Raphson iteration method are used for nonlinear solutions. A number of numerical examples are given to show the accuracy and efficiency of this method. Key words: finite strip, continuous structure, cable-stayed bridge, substructuring, catenary, nonlinearity, iteration.