Comparison And Analysis Of Stress And Deformation Of Continuous Rigid Frame Bridge With Different Bending And Slope Combination

With the rapid development of highway and railway transportation,a large number of curved ramp bridges inevitably appear,for smooth and comfortable driving,and better adapting to the limitation of topography,geomorphology,also for making bridges with more natural,increasing the visual aesthetic feeling,and with high linear demand of high grade highway,especially in the mountain areas.At the same time,on the highway or at the city interchange of the exit or the diversion,cross-line curved-slope bridges or ramp-ramp bridges often appear.Therefore,the emergence of the curved-slope composite bridge is the inevitable result in highway and railway bridge construction.Because number of the bending slope combination of long span continuous rigid frame increases,more and more problems are exposed,such as the straight girder crack number more than other same span continuous rigid frame bridge,the bridge slope under dynamic load may have too large shear deformation and bearing failure,girder displacement,expansion joint damage,etc.The effect of the curved continuous rigid frame bridge-slope stress and deformation of the factors is complex,the bridge must be designed for bending slope combination,which kind of turn-slope composed of bridge structure is relatively better?Designers are generally more aimless during their actual work.At the same time,there are few systematic studies on the stress and deformation characteristics of continuous rigid frame bridges in different curved and slope combinations.Therefore,systematic research of continuous rigid frame bridge of different combined bending-slope stress and deformation characteristics,analysis of the law,for the curved continuous rigid frame bridge-slope of reasonable design,construction and safe operation are of great significance.In this paper,based on the Yangjiawan bridge project,between the Ziyuan and Xing’an of the Guangxi province,the "bending" and "slope" combination parameters are changed,and the finite element software MIDAS/Civil is used to build 30 different curved slope combination models of the continuous rigid frame bridge.Through the mutual comparison and analysis of calculation results,and the results of the calculation of straight continuous rigid-frame bridge,the continuous rigid frame bridge under different curved slope combination situation mechanical characteristics,deformation characteristics and the influence law of "bending","slope" and the degree of influence are compared.1)Because there is defect in traditional indicating of characteristic parameters of curved bridge bending,the concept of relative bending radius is put forward,more than the central Angle can fully reflect the characteristics of the bending of curved bridge,using relative bending radius parameter analysis of research results,conducive to the popularization and application of research results.2)The influence of relative bending radius on different internal forces and deformation parameters of continuous rigid frame bridge is different.The distribution of torsion,lateral displacement,torsion angular displacement and supporting force of the main beam is very influential,and the influence on other internal forces and deformation parameters is relatively small or has little effect.When the relative bending radius is less than 6000m,the girder maximum torque,beam lateral displacement and torsional angular displacement are increasing sharply,as a bridge stage prestressed loads influence on counteracting force distribution of 18.0%or more.Therefore,in the design of curved bridge,reasonable radius and span combination should be selected to avoid the relative bending radius less than 6000m.3)The influence of the longitudinal slope of the bridge on the force and deformation of the continuous rigid frame bridge is relatively small,and in most cases the influence is not more than 5.0%～10%.4)Different bending-slope combinations make influence of the stress and deformation of continuous rigid frame bridge through the influence of "bending" and "slope" overlaying,though its influence degree is different from that of bend "flat",and is mainly of the influence of "bending".In the overall influence of "bending-slope",the influence of"bending" is more than 87%.In the case of deformation,the influence of "bending" is more than 88%.