Seismic Response Analysis Of Long-span Continuous Beam Bridges Based On The Different Incentive Methods

In recent years, China's earthquake more serious threat to people's life and property.Bridge structure is an important structure of traffic system,and is the hub of transportation systems engineering. The destruction of the bridge structure is not only led to a lot of direct economic losses, but also affect the production of post-disaster reconstruction and recovery efforts.In this paper, Liuku Nujiang River Bridge as the research background.From the structural characteristics of its own,seismic oscillation input mode, the dynamic response of the bridge structure three aspects departure,appliy the finite element analysis method using the finite element software MIDAS/CIVIL established three-span concrete continuous beam bridge finite element model.Draw the corresponding seismic response of bridge structures respectively, response spectrum consistent incentive,the schedule consistent incentive and schedule multi-point excitation are compared and analyzed. The following conclusions:1.Different seismic wave on the bridge structure has great impact forces and displacements. So it must be according to the actual bridge structure of the bridge site of choice with its consistent seismic waves.2. The response spectrum method based on consistent incentive can not consider the temporal effects of ground motion.It can only obtain maximum response. Time history analysis method can get the same bridge structure seismic response at any time, but time space effect cannot be simulated ground motions. For long-span continuous beam bridge, when the seismic analysis, multi-point excitation time history more realistic ground motion input mode.3 In order to be more consistent and accurate to compare response spectrum consistent incentive with the schedule consistent incentive,the schedule wave must be selected to adjust.The adjustment for the effective peak is equal to the bridge structure and response spectrum. This facilitates to compare response spectrum consistent incentive with the schedule consistent incentive.4 In the schedule of multi-point excitation,because of the different apparent velocity, different apparent velocity of seismic waves reach the end time of each pier is a certain time difference.So in the case of different time for input,long-span bridge structure seismic response has a considerable difference.Compareing multi-point excitation with the same vibration excitation there are great changes.When the apparent velocity is not great,traveling wave effect of earthquake can not be ignored.5 The shear and bending moment of the bridge structure in the response spectrum consistent excitation are greater than that in the schedule consistent incentive.The fulcrum shear in the response spectrum consistent excitation is 1.071?1.278 times.That in time history consistent excitation.and 1.109?1.243 times of the bending moment at mid span.