Research On Technical Measures Improving Resitance Capacity Of Downward Deflection Of Long Span PC Bridge

At present, the main problems of large span PC continuous rigid frame bridge at the mid-span deflection is too large, serious impact on the normal use of the bridge function, the research on how to improve the ability of resistance to deflection of midspan has great practical significance for long-span continuous rigid frame bridge.Based on the existing research results, discussed the various factors of long-term deflection of continuous rigid frame bridge, the analysis principle and somecompared mature reinforcement measures, to be the reference and application inthis paper.To monitor and control strictly on section height of Dadu River Bridge Construction in the process of change, analysis of rigid frame bridge in high pier and span under asymmetric, the numerical changes, in order to take preventive measures for correction. In order to Changhe River Bridge as the engineering background, using the finite element software Midas/civil to simulate the effect of longitudinal prestressed reinforcement, different tensioning weight, the diagonal prestressed tendons, tendon and the construction of concrete-filled steel tube skeleton oflong-span PC continuous rigid frame bridge midspan deflection are analyzed and compared.Through the derivation and calculation of the composite elastic modulus theory formula, using the existing concrete and steel constitutive model and Poisson’s ratio, through specific examples show that structural behavior of theoretical calculation and finite element analysis of the calculation results are consistent, canbe used as a general theoretical analysis of deflection calculation.According to the excessive midspan lag, puts forward the design of concrete-filled steel tube skeleton, calculation on force analysis of the region, concrete tensile stress play a significant role, section stiffness increased, reduced mid-span deflection.