Simplified assessment of cable-stayed bridges buckling stability

A simplified procedure for assessing of the overall elastic buckling stability of cable-stayed girder bridges at preliminary design stages is presented. The evaluation of the buckling modes and load factors is based on the analogy of taking a cable-stayed bridge deck as a beam–column on an elastic foundation. A new method of assessment of the model uniform continuous vertical stiffness, provided by the main span stays and reduced by the stays side span flexibility, is proposed. The results of this method are in good agreement with those of geometrical non-linear finite element analyses, typically performed at final design stages. The influence of the stay system, cable spacing, towers height, the live load pattern, and the number of the intermediate piers are finally analyzed.