Study On Bearing Behavior Of The Continuous Rigid Frame Bridge With High-pier And Large-span In The Life Cycle Considering The Steel Wires Corrosion Degradation

High pier and long span continuous rigid-frame bridge has been widely applied in thehighway construction in China because its structure has special advantages such as goodintegrity, large span capacity and clearance and so on.However, due to the environment ofsuch bridges is generally relatively poor, common reinforced bars and pre-stressed concretestrands are prone to corrode,and especially the corrosion of strands has greater impact on thebridge carrying capacity.Therefore, the study of the impact of steel corrosion on the bearingperformance of continuous rigid frame bridge and reasonable estimation of the key nodeswhen bearing capacity degrades, not only have practical significance to bridgemaintenance,but also show theoretical and technical support to the extension of the structureservice life.Firstly, this paper proposes the concept of bridge life cycle based on corroded reinforcedbars, which gives the basic constraint principles for the prediction and calculation ofcorrosion.Secondly, the article analyzes the corrosion mechanism of steel strands and gets aclear strand corrosion morphology; in addition it has studied the corrosion strandsperformance evaluation model, then the limit state equations of bearing capacity of flexuralmembers on basis of corroded reinforced bars is given.Thirdly,the dissertation systematicallyanalyzes the corrosion models of reinforced bars under carbonation corrosion and chloridecorrosion, also the corrosion model of common reinforced bars and pre-stressed steel standsunder chloride corrosion is improved.Next,as the background of a typical high pier and longspan continuous rigid-frame bridge in Tongchuan area of Shaanxi province, throughcalculating and analyzing the corrosion of pre-stressed steel stands under carbonationcorrosion and chloride corrosion, the paper determines the forecast results of steel standscorrosion of this bridge under given life cycle.Finally, the article uses the forecast results toanalyze and calculate the bearing capacity performance of this bridge in the give life cycle,and it has realized the aim to do the bearing capacity performance degradation analysis ofhigh pier and long span continuous rigid-frame bridge in the given life cycle.The following conclusion can be drawn by the study of this paper.As for high pier and long span continuous rigid-frame bridge in its life cycle, the carbonation corrosion has littleeffect on the steel strands corrosion and this effect can be negligible,but on condition that theimpact of steel stands corrosion caused by chloride erosion on the bridge bearing capacityperformance must be considered.And in the case that the steel stands corrosion is taken intoaccount, the flexural performance of the main beam and the crack resistance performance ofconcrete for this type of bridge notably degrade, while the shear performance of the mainbeam and the compression resistance performance of the concrete can still satisfy therequirements of specifications.This paper’s research results is of certain referential value forthe study of similar problems.