The Remaining Bearing Capacity Evaluation Of Continuous Rigid Bridge And Reinforcement Analysis

The old bridges was increasing, whether the residual bearing capacity of it couldsatisfy the requirements of modern traffic gradually attracted attention, evaluating thebearing capacity of old bridges accurately is becoming more and more important.Reinforcement is a good method to continue the bearing capacity of old bridges, whichhas a good social and economic benefits. Continuous rigid frame bridge has been usedwidely because of its’ unique mechanical properties, in the process of application, thediseases of it also reflects a certain particularity. Based on above research background,this paper mainly carried on some work:①This paper focused on the diffusion of chloride ion in concrete, built the formulaof chloride ion diffusion coefficient based on the water cement ratio, at the same time,carried on the correction by considering the actual concrete stress, provided the basis topredict corrosion time of steel in the normal operation bridge.②conducted a rapid corrosion test of prestressed reinforcement to get theprediction model of steel strand corrosion in practical structure. At present, much moreresearch focused on the ordinary steel corrosion and the mechanical properties ofcorroded, while prestressed reinforcement is relatively less. Aiming at the shortcomings,built the relationship of the prestressed reinforcement corrosion and the stress and thetime, used the current density as a transition to assess the bearing capacity of the bridge.③proposed a calculation model based on crack extension and corrosion ofreinforcement and the corroded reinforced difference，the formula can well adapt to theevaluation of existing continuous rigid frame bridge. The paper introduced the existingassessment formulas for bearing capacity of bridge, analyzed the applicable conditionsand the insufficiency of each formula, and get a new formula.The formula could beapplied well to the bridge diseases appeared in various situations.A practical examplewas calculated and analyzed about the bearing capacity.④Established the finite element model, based on the changes in the compressionzone edge compressive strain of concrete structure to analyze the influence of thecommon diseases to the bearing capacity in continuous rigid frame bridge, for exampleWeb diagonal cracks and longitudinal cracks in the top plate. Meanwhile the paperdiscussed the variation of stress cracks in surrounding area after the crack appeared. ⑤analyzed the variation of compressive strain in the compression zone edge afterthe reinforcement of continuous rigid frame bridge by the finite element model,, and geta better reinforcement effect.