State Analysis And Countermeasure Evaluation Of Existing Curved Single Column Pier Bridge Under Earthquake

In cities where land is scarce nowadays,single-pier bridges are widely used on urban viaducts and ramp bridges of expressways because of the advantages of small space under bridges,wide vision and few underground works.In order to solve the problem of vehicle convergence in different directions in interchanges,single-column pier structure is usually used to build curved girder bridges.However,due to the bending moment coupling problem of the curved bridge and the single bridge pier supporting only the upper bridge deck,the curved single-column pier bridge is easily damaged,especially under strong earthquakes,causing the upper tribe beam and even the bridge to collapse.For curved bridges with single pier that do not meet the performance requirements under strong earthquakes,all these bridges are demolished and rebuilt,which not only obstructs traffic and affects people's normal travel,but also wastes building materials.Some reinforcement measures are taken to improve the piers,reduce the seismic response of piers and improve their seismic performance,which can greatly reduce engineering expenditure and increase the use lifetime of existing bridges.,reduce construction period,etc.The main work of this paper is as follows:(1)Taking a bridge with a single column pier as the research background,the finite element model of the whole bridge is established by using the finite element software OpenSees under the action of longitudinal and transverse seismic forces respectively,selecting the appropriate seismic wave input direction.The seismic response of the whole bridge is analyzed,and the failure state of the single pier bridge is judged by the deformation failure criterion,the strength failure criterion and the improved deformation and energy failure criterion.The results show that the piers are destroyed under strong earthquakes.(2)In this paper,three different reinforcement materials,CFRP,DFRP and PUFA,are used to reinforce the pier respectively.The appropriate constitutive relationship is selected according to the pier section,the model is rebuilt by using the finite element software Opensees,and the seismic response is analyzed.The reinforced pier is compared with the unreinforced one,and summarized the influence of the type of reinforcement material on the reinforcement effect.(3)In order to further analyze the influence of different wrapping forms of the same material on the reinforcing effect,this paper establishes three different forms of reinforcement models when the amount of carbon fiber cloth is used,analyzes the seismic performance of piers under different package forms,and summarizes the strips.The effect of the distance between the reinforcement effects.(4)In order to analyze the influence of seismic isolation bearing on the seismic performance of the bridge structure,this paper uses the friction swing isolation seismic isolation bearing instead of the original ordinary rubber bearing for analysis,respectively under the action of longitudinal seismic force and lateral seismic force.The finite element model was re-established,and the damping effect of the friction-isolated isolation bearing was compared and the lateral and longitudinal damping effects were compared.