Study On Seismic Mitigation And Isolation Measures And Dynamic Analysis Of Self-anchored Suspension Bridge With Single-tower

Taking a certain self-anchored suspension bridge with single-tower as engineeringbackground, using large–scale FEM software Midas/civil to build the space finite elementmodel, exploring dynamic characteristics, seismic performance,seismic mitigation andisolation research of self-anchored suspension bridge with single-tower, the main researchcontents and results are as follows：（1）Based on the method of multiple Ritz, structure natural vibration period andvibration model are calculated respectively with consideration of pile-soil-structureinteraction(pile-soil spring model) and irrespective of pile-soil-structure interaction(fixedmodel).Analysis shows that considering the pile-soil interaction-structure, the frequencies ofthe whole system reduced, natural vibration period increases accordingly, that is the flexibilityof whole system increases. After consideration of pile-soil-structure interaction, a frequencyof structure is decreased by25%, namely pile soil-structure interaction has influence on thestiffness of self-anchored suspension bridge with single-tower, so pile soil-structureinteraction should be considered in dynamic calculation.（2）In a consensus input by using nonlinear time-history analysis method to analyseseismic response of pile-soil spring model and fixed model, analysing of the seismicperformance. Analysis shows that, under the action of earthquake,beam end and top towerdisplacement of self-anchored suspension bridge with single-tower of floating type is big, soseismic mitigation and isolation measures should be considered to decrease seismicresponse.the longitudinal shearing in fixed model is big6.6%than pile-soil spring model,beam end and top tower displacement small29.4%.Namely fixed model calculates structurestiffness too large, The calculation results partial conservative, the displacement estimateshortage.It is suggested that the bridge seismic dynamic analysis in consideration of ahigh-rising structure interact with each other.（3）By using nonlinear time-history method to explore the installation position,numberand main design parameters of isolation device viscous dampers,and optimize the main designparameters of damping coefficient C and speed index ξ. The results showed that, under thelongitudinal seismic action, displacement of beam end is reduced by77%, top towerdisplacement is reduced by78%.（4）By using nonlinear time-history method to analyse the installation,number ofintegral device lead rubber bearing. The results showed that, under the longitudinal seismic action, displacement of beam end is reduced by77%, top tower displacement is reduced by72%.（5）Viscous dampers and lead rubber bearing increases the seismic moment response atthe bottom of auxiliary pier and the junction pier, but are less than the pier bottom sections ofequivalent yield moment..Under earthquake action, the displacement response is control rolein single tower self-anchored suspension bridge, so the viscous dampers and lead rubberbearing can be used for the seismic mitigation and isolation design of the single towerself-anchored suspension bridge.