Research On The Impact Factors Of Damage And Reinforcement Of The Continuous Rigid Frame Bridge

Continuous rigid frame bridge has been widely used by the large carrying capacity,traffic comfort,material economy,easy construction and maintenance.Investigations revealed that the defects of different degrees of cracks,continued down warping across and bearing capacity reduction widely happen on continuous rigid frame bridges in service.Therefore,the research of continuous rigid frame bridge damage factors and reinforcement technology is particularly important.This paper,study on a double thin-wall high piers of long-span continuous rigid frame bridge as an example,according to the damage detection and Midas/Civil finite element numerical simulation results,value the reinforcement effect of unbond prestress external reinforcement technique,bond prestress external reinforcement technique and steel plate-pasting technology.This paper analyzes the influence factors of continuous rigid frame bridge common diseases.Firstly,proposed main influence factor of continuous rigid frame bridge midspan deflection sustainable development: the loss of pre-stress,creep and shrinkage of concrete,structure cracks and structure weight.Based on the basic theory and calculation method,this paper expounds the mechanism of these factors affecting the midspan deflection sustainable development.By changing the parameters and quantitative analysis,preliminary obtained the change rule between the midspan deflection and the influence factors,grasp the sensitivity of various factors in different span deflection.Through access to relevant statistical data,the common carry out influence factors of continuous rigid frame bridge cracks are analyzed.Combined with the bridge site cracks field inspection report,based on results of the Midas/Civil finite element simulation,static and dynamic characteristic of bridge are analyzed.Found that the pier top compressive stress is relatively low,the transverse stiffness of box girder as a whole is low,the continuous downwarping phenomenon in the middle of span is obvious,weak stiffness at the middle of midspan.According to the principle of reinforcement design and calculation theory,scheme of unbond prestressed reinforcement method,bond prestressed reinforcement method and steel plate-pasting reinforcement method was determined,the optimal strengthen scheme was chosen by comparing static and dynamic analysis result before and after the reinforcement.The study found that unbond prestressed reinforcement effect was the best,suggesting that continuous rigid frame bridge mainspan above 100 m using this method for reinforcement.At the same time,by adjusting the steel beam bending position of punching and steel plate position,analyzing the change rule of deflection and stress,optimize the reinforcement scheme analysis.