Experimental study on in-plane nonlinear vibrations of the cable-stayed bridge

Abstract

The nonlinear dynamic behaviors of the cable-stayed bridge are considerably complicated and very interesting. In order to explore the nonlinear behaviors of a cable-stayed bridge, a scaled physical model with Xiangshangang Bridge as the prototype is established and the systematical experiments are carried out. Firstly, the physical parameters, especially initial tension forces, of cables are measured by free vibration test and the data is dealt with FFT and filtering technology. The corresponding modal analysis is conducted and the test results are in good agreement with those obtained by OECS model and MECS model, which shows the experimental effectivity. Then, the free vibrations of cables are analyzed and the 1:1 resonance between different cables is revealed. Thereafter, by applying a single excitation to the beam, the nonlinear resonance of the cable-stayed bridge is studied and the rich nonlinear phenomena are observed, such as the parametric vibration, harmonic resonance, multiple internal resonance, primary resonance and cable–cable coupling vibration. Finally, some interesting conclusions are drawn, for example, the large amplitude vibrations of cables can be induced when the nonlinear resonance conditions are matched under external excitation.