Based On Numerical Experiment To Analyze The Seismic Response And Damage Characteristics Of Pier Under Offshore Ground Motion

In recent years,the construction of sea-crossing bridges in China has developed rapidly,and it is difficult to inspect and repair the post-earthquake damage of underwater piers,and the use of seismic isolation system for girder bridges has become an important choice.Relevant studies show that there are great differences in the vertical and horizontal components of offshore and terrestrial ground motion,and it is necessary to analyze and determine the seismic response and damage characteristics of seismic isolation piers under offshore ground motion.In order to solve this scientific problem,this paper first uses the finite element nonlinear analysis software ABAQUS to establish the elastoplastic analysis model of bridge piers,and verifies the accuracy of the model by comparing it with the shake table test results.Secondly,the above modeling method is used to establish a numerical shake table analysis model,and the seismic response characteristics and damage characteristics of reinforced concrete piers under seafloor and terrestrial seismic action under different seismic peak acceleration conditions are compared.Furthermore,the incremental dynamic analysis method was used to analyze the vulnerability of the pier structure,and the damage probability of the lower pier for seabed and land seismic action was studied.Finally,a refined seismic isolation pier seismic response analysis model is established to determine the response characteristics of the lower seismic isolation pier and vibration isolation support for seabed seismic action.Based on the above research,this paper draws the following conclusions:(1)It is necessary to input three-way seismic load in the structural seismic response analysis by comparing only the horizontal two-way seismic load and entering the vertical seismic component at the same time,which will amplify the horizontal response of the structure.(2)The seismic response of ordinary reinforced concrete piers and vibration-isolated piers under seabed seismic action is greater than that of land seismic action.Moreover,compared with land seismic,the probability of damage of bridge piers under seabed seismic action is increased.(3)Compared with ordinary piers,the seismic response of seismic isolation piers is significantly reduced under seismic action,and the top displacement and acceleration of piers are significantly reduced.Compared with the plate rubber bearing,the relative displacement of the lead core rubber support is smaller under the action of earthquake,and the lead core rubber support is less likely to be damaged under the action of large earthquake.