The Analytical Approach And Application Study Of Vortex-Induced Vibration Of Long-Span Bridge Based On Partial Correlation

The research of vortex-induced vibration (VIV) of long span bridge is reviewed in this thesis, several classic semi-empirical VIV model and the three-dimensional vortex shedding characteristics of line-like bluff bodies are introduced. With considering the partial correlation of vortex-induced forces, the three-dimensional analytical approches for long span bridge are proposed on the basis of Scanlan’s semi-empirical linear model and nonlinear model, and pressure measurement tests of section model with blunt body. The validity of proposed approches is confirmed by simply supported aeroelastic models, and the reference for accurately evaluating the VIV response of long-span bridge is provided. The main research contents of this thesis are shown as follows:1. The research of VIV on long span bridge is reviewed, the current research methods for VIV problem are summarized, and several VIV examples of some classic bridge and their mitigation countermeasures are also listed.2. In order to provide theoretical foundation for proposing three-dimensional VIV analytical approches of long span bridge, Scanlan’s semi-empirical linear and nonlinear VIV model which were adopted widely in civil engineering are introduced. And the three-dimensional vortex shedding characteristics of some classic bluff bodies are reviewed, furthermore, the identifying method of parameters in the semi-empirical VIV model and the existing theory about spanwise correlation of vortex-induced forces are discussed.3. With considering the partial correlation of vortex-induced forces along span, the linear and nonlinear analytical approches based on Scanlan’s linear and nonlinear VIV model are proposed respectively by using frequency-domain analysis, and the parameters identification method in the nonlinear model is improved. At last, the three-dimensional VIV analytical approches are specially proposed for long span bridges.4. Several section models with typical bluff body (including rectangular, trapezoidal, and streamlined girder) are made for pressure measurement tests by using free vibration method, the spanwise correlation of vortex-induced forces and its influence are studied in details, and the correlation functions are fitted based on the vortex-induced forces correlation tests. The correlations of two simply supported aeroelastic model (rectangular and trapezoidal) are studied in details and compared with section model results, and the effects of mode shape on spanwise correlation of vortex-induced forces are studied as well.5. VIV tests for section models and simply supported aeroelastic models with the same scale are conducted respectively. To confirm the validity of proposed approach, the VIV responses of section model are interpret into aeroelastic model by using the proposed three-dimensional VIV analysis theory of long span bridge, and compare the tests results with the aeroelastic model. Finally, a long span cable-stayed bridge is taken as an example for illustrating the application of proposed approach in VIV analysis of long span bridge.