| Due to the influence of topography in Southwest China,the upper arch bridge has been the main bridge type of bridge.In recent years,there are more and more large-span arch bridges and projects under construction.Arch bridges play an important role in traffic engineering.If damage occurs under the earthquake,it will seriously threaten the life and property safety of the people.At present,the seismic research of the upper arch bridge is mainly aimed at the earthquake damage of the main arch ring,and few researches on the seismic resistance of the arch buildings.In the case of the arch bridge span is not very large,the seismic problem of the arch building may not be prominent,but after the span increases,the span and height of the arch building will be significantly increased,and the seismic problem may become the main contradiction of the bridge design.The piers of the arch of the open web Arch Bridge show different characteristics of height and height,which have similar seismic problems with high and low pier bridges.At present,scholars have rich research results on the seismic response of the girder bridges.This paper hopes to compare the differences between the seismic response and the damping control scheme of the arch buildings and the same structure.The research results of the seismic research of the beam bridge are applied to the arch building,which provides theoretical basis and reference for the seismic and seismic design of arch bridges in China.Taking the longspan up bearing reinforced concrete arch bridge as an example,based on the finite element calculation software SAP2000,the seismic response characteristics and the control scheme of the arch building are analyzed.The main research contents and conclusions are as follows:(1)Based on the analysis software SAP2000,the finite element analysis model of the whole bridge is established and the nonlinear time history analysis is carried out.Based on the research results at home and abroad,the seismic response characteristics of the long-span reinforced concrete arch bridge are defined.By extracting the acceleration time history response of the pier base on the arch and transforming the power spectrum,the paper analyzes the distribution characteristics of the acceleration energy of the pier base after the elastic filtering of the main arch ring;evaluates the filtering effect of the main arch ring on the arch by comparing with the power spectrum of the seismic wave itself;then analyzes the structure on the beam arch and the same form of beam bridge from the angle of acceleration and displacement The difference of seismic response is discussed,and the influence of main arch ring on the "elastic filtering" of the arch building is discussed.The results show that the elastic filtering of arch ring reduces the high frequency vibration energy input into the arch building,enlarges the energy in the low frequency section,and the influence on the arch near the arch is much greater than that of the arch foot.The elastic filtering makes the pier more easily enter the plastic stage,and the displacement of the pier top and acceleration,the displacement of the support and the displacement of the beam are larger than that of the continuous beam of the same structure.In addition,the existence of arch damping and the greater stiffness can reduce the influence of filtering effect.(2)Based on the theory analysis method of vulnerability,according to the seismic damage characteristics of the girder arch bridge of long-span up arch bridge,the finite element model of arch bridge is established by SAP2000 finite element software and the seismic time history response analysis is carried out.The seismic failure state and damage index of the columns,supports and main girder members on the arch are specified.The probability density of the components is calculated by combining the seismic response function of each component.Finally,the probability density is calculated Taking the probability of exceeding the specified damage index of each component,the vulnerability curve of the columns,supports and main beams on the arch is obtained;the vulnerability curve of the beam and bridge members with the same structure on the arch is calculated and compared with the same method.Finally,by considering the correlation between different components,the first and second-order boundary methods are used to calculate the vulnerability curve of the beam and Bridge on the arch and the same structure System vulnerability curve.The research shows that when the pier is high(arch foot position),the damage probability of the columns on the arch and the bridge piers of the same structure is not different.With the decrease of the pier height,that is,the damage probability of the columns on the arch is significantly higher than that of the same structure from the arch foot to the arch top position;when it is close to the arch crown,because the damping of the arch ring consumes most of the energy,it is transmitted to the support after passing the arch ring The energy of the beam bridge is smaller than that of the beam and bridge support,so the damage probability of the beam and bridge bearing is greater than that of the arch bearing.Because the damping of the arch ring consumes most of the energy,the main beam will not be damaged under earthquake action.The system vulnerability of the beam bridge is higher than that of the arch building,and the system vulnerability is stronger than that of each component.It is not safe to evaluate the structure by using the vulnerability of each component.(3)This paper studies the damping control of arch buildings by two schemes of arrangement of viscous damper and adjusting the stiffness of supports.The optimal damper parameters are obtained.From the aspect of displacement and internal force response,the effect of damper on the control of the damper on arch building is analyzed.Then,based on the current adjustment scheme of simple supported beam bridge in mountainous area,the arch building and the phase are analyzed and compared The difference between the adjustment scheme of the beam and bridge bearing with the structure,the paper optimizes the adjustment scheme of the support of the arch building and puts forward the relevant suggestions.It is found that the damper can effectively reduce the relative displacement of pier beam,but the internal force of the members will increase to some extent.In principle,the layout scheme of bearing stiffness of arch building reduces the stiffness of the support of the low pier by increasing the rigidity of the high pier support.However,the arrangement of the supports on the arch is different from that of irregular beam bridges.The bearing stiffness of the high pier should be higher than that of the beam bridge,and the approximate equivalent or smaller stiffness value should be set at the low pier. |
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