Transverse Seismic Mitigation And Isolation Design And Seismic Response Analysis Of Continuous Beam Bridges

With the advantage of beautiful shape, reasonable stress, smooth pavements, comfortabletraveling, continuous beam bridges have wide development prospects in the flat areas. In thepast few years, the frequent earthquake disasters have caused a large number of losses in ourcountry, therefore, it is significant to research the analysis of seismic response of continuousbeam bridges which occupy an important position in traffic engineering.For moderate long bridges, the first natural period of the bridge is the first longitudinalperiod, while the first transverse period is the second period.Whether it is possible that thetransverse period may exceed the longitudinal period. In this paper, taking a continuous beambridge which its first-order periodic is transverse bending as the research object. Using thelarge-scaled universal FEM software Midas/Civil to build the space finite element model,exploring natural vibration period, seismic performance, transverse seismic mitigation andisolation research of continuous girder bridges. The main research contents and results are asfollows:1. Based on the basic principles of the dynamics, the first-order transverse bending’snecessary conditions of multi-span continuous beam bridge are caculated by elasticallysupported continuous beam model, which is simplified from the actual structure and thetransverse boundary of both ends are rigidity constraints. The necessary conditions are asfollows: two spans>11.48, three spans>11.45, four spans>11.31, five spans>11.31,where now kL3/8EI. With further analysis, the necessary conditions also couldexpressed as: the longitudinal stiffness of bridge is two times greater than the transversestiffness of the bridge.2. Establish continuous beam bridges space finite element model with Midas/Civil, thelongitudinal and transverse dynamic characteristics are analysed and compared with thetheoretical results. The result shows that theoretical analysis result and the numerical solutionis consistent.3. According to the actual soil conditions of the bridge site, analysis the seismic response spectrum of continuous beam bridge which the first vibration mode is transverse bend, andanalysis the longitudinal and transverse seismic response of continuous beam bridges basedon several different design parameters.4. Using artificial fitting seismic waves and dynamic time-history method to respectivelycompare the seismic response characters of continuous beam bridge, under two workingconditions of transverse bending and longitudinal bending.5. Using lead-rubber bearing and fluid viscous damper, discuss the transverse seismicisolation effect of multi-span continuous beam bridge, compare and analysis seismic isolationeffect of the two seismic isolation devices by changing their main design parameters.