Dynamic Response Analysis Of Deep-water Continuous Rigid Frame Bridge Under Earthquake And Wave Action

In order to adapt to the rapid development of contemporary transportation industry and improve the pace of building a transportation power,the construction of bridge engineering is increasing day by day.Due to the coupling action of wind,wave,earthquake and other loads,the safety and stability requirements of Bridges in deep water environment are higher than those of land Bridges.However,most of the current researches mainly focus on the dynamic response analysis of a single pier or lower foundation under the action of earthquake and wave,and the research on the dynamic response characteristics of the whole bridge is extremely lacking.Therefore,this paper establishes single-pier and continuous rigid frame Bridges in deep water environment and makes the following research:(1)the different slenderness ratio of bridge pier model was established,using the added mass ratio method,considering the dynamic water pressure and supplemented by Morison equation method and the radiation wave method analysis the natural frequency of vibration and seismic response of bridge pier under the influence of dynamic water pressure.It is found that the slenderness ratio of bridge piers can be used as an effective index to define the influence degree of hydrodynamic pressure and the applicable scope of different calculation methods,and the safety of deep water bridge piers in the range of slenderness ratio with greater influence degree should be considered.For bridge pier model of slenderness ratio is roughly below 50,Morison equation method,the error is bigger,is not applicable,at this time give priority to choose added mass ratio method and the radiation wave method;For the bridge pier model with large length and thin,the applicability of the three methods is good.(2)The continuous rigid frame bridge structure is established,and its dynamic response under the action of near field,general field and far field seismic waves is analyzed.Through analysis shows that compared with the general site seismic waves,near and far field seismic waves magnified the dynamic response of the structure,the existence of water may make amplification effect is more significant,so for the water of the structure of the seismic design,it should be emphatically considered ground shock effect of the pulse near and far field seismic waves have class for a long period of time harmonic component of structure dynamic response of the amplification effect;The influence degree of hydrodynamic pressure on the dynamic response of structure is related to the spectral characteristics of seismic wave,and the contribution of seismic wave to the peak change rate of dynamic response is the greatest.(3)The dynamic response analysis of the continuous rigid frame bridge structure under different wave parameters is carried out.The results show that the change of wave height has a great influence on the dynamic response of the structure.The contribution of water depth to the dynamic response of the structure is mainly reflected in the superstructure.The influence of the period change on the dynamic response of the structure is limited.When the period is greater than 7.5s,the change of the maximum value of the dynamic response is almost negligible.(4)continuous rigid frame bridge structure for the earthquake and the dynamic response analysis under the joint action of waves,the results show that the earthquake and the joint action of waves,under the seismic action effect on dynamic response of bridge pier dominate,wave action to change the size of the structure,but did not change the waveform and the peak times.