Effect of Dynamical Behavior of Long Span Cablestayed Bridge with Ambient Medium

The actual bridge structures are not situated in the vacuum environment, so the dynamical behavior of the bridge structure will be affected with the geometrical deformations and the mass distributions due to the variation of the ambient medium, especially along the augment of bridge span. Taking into the effect of the static wind, temperature and deep water account synthetically, this paper analyzes the variation and influence of matrix {M} and matrix {K} with those three ambient mediums by starting out with the dynamical behavior equilibrium equation. A dynamical finite element model of E Dong Bridge with main span of 926m is built to research the rules between dynamical behavior of cable-stayed bridge and those ambient mediums. The results of calculation indicate that natural vibration frequency of bridge structure will reduce drastically and follow with oscillation mode coupling phenomenon in high wind velocity caused by the three-dimension nonlinear ingredients, the additional mass induced by water effect will reduce the natural vibration frequency appreciably and follow with the local vibration shape of main pier and bridge tower exist in the range of lower frequency, as to the temperature effect, the natural vibration frequency variety is not obvious, can be ignored during analysis.