| As compared to the cable-stayed bridge with double cable planes, the cable-stayed bridgewith single cable plane has better view, and however it is weak in the torsional performance,in particular for the bridge under construction. During the deck erection, the structural systemvaries continuously, the final structural state of the bridge has not yet formed, structuralstiffness is much less, and under the wind and earthquake actions, structural deformation andalso the stability of the bridge may become more serious. Therefore in this thesis, by takingthe Fuyang Lushan Bridge as example, the wind and earthquake resistances of the bridgeduring the whole construction phase have been investigated numerically.Firstly, by using the MIDAS/Civil software, the reasonable states of the bridge incompletion and construction stages are simulated. Secondly, the dynamic characteristics of thebridge during deck erection have been analyzed by the subspace iteration method. Thirdly, theaerostatic and aerodynamic stability of the bridge during deck erection have been investigatedby the aerostatic and aerodynamic analysis. Finally, the response spectrum analysis isperformed to investigate the seismic performance of the bridge during deck erection. Throughnumerical analysis, the evolutions of the dynamic characteristics, wind stability and seismicperformance of the bridge during deck erection are revealed and discussed.The results show that with developing of the deck erection:(1)The natural frequencies ofthe bridge decrease sharply during the early erection stages, but decrease slightly at the latererection stages;(2) the critical wind speeds of aerostatic and aerodynamic instability decreasemonotonously during erection, and the worst aerostatic and aerodynamic conditions occur atthe bridge in completion;(3)in the seismic analysis, more attentions should be paid to thelateral displacements of the towers and the girder and also their internal forces. |
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