The Analysis And Research On The Bridge’s Seismic Resistance, Wind Resistance And Their Influence Factors

On the background of the increasing of strong earthquake and wind hazard, more and more bridges are faced with both tribulations of wind and earthquake. It is very important that the bridge as one of the most important traffic engineering should be able to resist the earthquake and wind. The dissertation analyzed the difference and conference between the bridge’s seismic and wind resistance from the input, system and output based on the cable bridge, deeply analyzed the character of earthquake response and wind response, carefully studied the affecting factors of the ability of seismic and wind resistance, discussed the connection of seismic and wind resistance in the respect of structure design and anti-vibration measure.The dissertation firstly reviewed the bridge’s seismic resistance and wind resistance development history, research condition and hot problem. In the past, the research on the seismic resistance or wind resistance is going to be completed, while both as the dynamic load, the effect of the earthquake and wind on the bridge has never been studied.From the input perspective, the second chapter researched and compared the character of earthquake and wind such as formation, existing way and their affecting factors. From the point of energy, the chapter analyzed and compared the energy distribution of the earthquake and wind, the result dictated that the dominating frequency of the earthquake is much higher than1.0Hz, while that of the wind is less than0.1Hz.The libration character of the structure has relationship not only with the load but also the structure itself. Connecting with the dominating frequency of the earthquake and the wind, the third chapter analyzed and discussed the sensitivity of different type of bridge to earthquake and wind, compared the sensitivity of the factors which affect the libration character, the result dictated that the mass and the rigid are not the same sensitive to the ability of seismic and wind resistance. In order to aviod the resonance under the earthquake, changing the mass is more effective, while for the wind, changing the rigid is more effective.Based on the research on the bridge’s seismic resistance and wind resistance in the past, according to the study on the character of the earthquake and the wind and the analysis on the structure’s vibration character, the fourth chapter compared the seismic and wind resistance from the aspects of design theory, computation methods, structure response and anti-vibration measures.According to the above analysis on the different sensitivity of various type bridges, the cable bridge’s character of seismic resistance and wind resistance is more complex. Taking the Xiangshan Bay Bridge as example, analyzed and compared the bridge’s seismic response and wind response, accurately researched the effect of structure system and pile-soil on the bridge’s seismic and wind-resistance response, firstly studied the pile-soil effect on the bridge’s response under the wind. The result dictated that the effect of structure system and pile-soil on the bridge’s seismic and wind-resistance response is different, the pile-soil effect can not be ignoranced in the wind resistance of the long-span cable bridge.Finally, considering the cable bridge’s big possibility facing the earthquake and wind, how to reasonably design the structure and choose the best suitable anti-vibration measure is very important for the cable bridge. Taking the exsited bridges for example, discussed the connection of seismic resistance and wind resistance during the cable bridges’structure design, and studied how to choose the anti-vibration measures to satisfy the demand of seismic resistance and wind resistance. The aerodynamic measure is proved to be superior and effective to balance the cable bridge’s seismic resistance and wind resistance by using the CFD analysis and wind tunnel test.