Nonlinear approach of vortex-induced vibration for line-like structures

• A nonlinear approach for interpreting the test results of section model into prototype structure was proposed.
• Partial correlation of vortex-induced aerodynamic force along the span was considered in this method.
• The identifying method of parameters in this semi-empirical vortex-induced force model was improved.
• The validity of proposed method was confirmed by sectional model wind tunnel tests and observed results in field.

Vortex-induced vibration (VIV) is one of self-excited vibration with limited amplitude, usually occurring on long and slender structures with lower damping. A nonlinear method based on Scanlan's nonlinear vortex-induced vibration model is proposed in this paper for interpreting the test results of section model into prototype structure. Partial correlation of vortex-induced aerodynamic force along span is considered in this method, and the identifying method of parameters in the semi-empirical mathematic model is improved. Validity of proposed theory is confirmed by section model tests and observed results in field of a long-span suspension bridge.

A nonlinear approach is proposed for interpreting the test results of section model into prototype structure, and partial correlation of vortex-induced aerodynamic force along the span is considered in this method. Validity of the proposed theory is confirmed by section model tests and observed results in field of a long-span suspension bridge. The graph shows the reduced factor of section model with elastic suspension. It is obvious that the reduced factor varied with VIV amplitude and spacing along span. The reduced factors of line-like structures at any vibration mode show a similar trend with this graph, and it can be calculated by the proposed approach. Consequently, the VIV amplitude of structures can be determined by section model wind tunnel test results. Reduced factors for section model (η=amplitude; D=depth of girder).Figure optionsDownload as PowerPoint slide