State Analysis And Countermeasure Evaluation Of Single Column Pier Bridge In Service City Under Earthquake

Single column pier bridge with visual transparent,beautiful shape,space saving advantages,have been widely used in the construction of city road and highway,in the city land increasingly tense,single column pier bridge is more and more high proportion.But at the same time,single column pier bridge is also prone to various types of damage,such as partial load box girder overturning under overload,collapse,structure beam occurs in cantilever beam damage,especially the single column pier occurred under the action of earthquake damage easily,resulting in the tribe of bridges collapsed.Blocking the post disaster relief supplies,thus exacerbating the earthquake disaster.Up to now,there have been many researches on seismic performance of single pier in seismic field,but there is less research on the seismic performance of single pier bridge.The evaluation of single column pier bridge under earthquake condition,when the earthquake does not meet the performance requirements of the appropriate methods of strengthening,improve the seismic performance,to promote social production,ensure safe transportation lifeline,has important significance of saving the budget expenditure.The main work of this paper is:(1)Based on a joint Ramp Bridge with a single column in a city,the finite element software OpenSees is used to select reasonable structural unit type,material constitutive relation,fiber cross section and other parameters.Establish the full bridge model.(2)Select the appropriate seismic wave,carry out the full-bridge dynamic analysis,apply the single parameter failure criterion and the two-parameter failure criterion based on the deformation and energy to evaluate the state of the single-pillar bridge and compare the two judgment criteria.(3)When the peak acceleration of the earthquake is large and the structure exceeds the limit state,the bridge is reinforced with carbon fiber(CFRP)cloth,and the model is established with OpenSees to analyze the dynamic response.The state ofthe pier is determined and the reinforcement Before contrast.The results show that the CFRP cloth can play a good reinforcement effect,the displacement and ultimate displacement ratio of the top of the pier are obviously decreased and the damage index is also reduced.(4)In this paper,the reinforcement effect of CFRP cloth is further studied.The effects of different CFRP reinforcement thickness and reinforcement type on the reinforcement effect were investigated.The CFRP cloths of 2,5 and 8 layers were wound on the original model respectively,and the reinforcement effect obtained by different reinforcement layers was compared.Under the same conditions of CFRP,the models of strip wrapping and integral wrapping were established respectively.And the effect of different strip spacing on reinforcement effect.Summary the conclusion of this paper,and prospect the development direction of CFRP reinforced concrete pier column.