Study Of Evaluation On Capacity Of Existing Reinforced Concrete Bridges Based On Considering Damage Factors As Steel Bar Corrosion

Due to concrete carbonation, steel-bar corrosion, vehicle load increasing and deficiency of maintenance, some bridges expose various structural deterioration ,and it maybe cause the loss of bearing capacity and the decrement in performances of structures resulting in unsafe factors compared with the requirements of the design code. Therefore, the reasonable evaluation on the bearing capacity of existing bridges is an urgent issue in order to insuring the safety of the structures.In this paper,base on considering the factors as steel-bar corrosion,concrete deterioration,bond strength decay which influence the structure bearing capacity, studying the relation between damage and bearing capacity. introducing each damage evolvement rate into the structure resistance expression of flexural capacity and shear capacity , constructing the resistance expression base on variable ingredient of time and accordingly,by construct limit state equation,study the reliability change with time,combine the dynamic reliability with damage assess, the evaluation and forecast of existing bridge capacity and life is come ture.In accordance with the study process of"concrete carbonation-mechanical properties of corrosive steel-bars and concrte degenerate—deterioration of mechanical properties of corrosive reinforced concrete members—durability estimation of corrosive bridge structure bearing capacity",systematical study of corrosive concrete structures, is summarized by the author as follows:(1) The rule of carbonation depth changed by time is discussed, it make the basis of the next studying of the corrosive steel-bar (2) various of factors which influence the capacity of bridge is analyse.(3)by study the factor which lead the degenerate of capacity of bridge, probe and discuss the method of Nonlinear finite element to simulate the corrded reinforced beam,and with the help of ANSYS, the degenerate rule of mechanical properties of different corrosive ratio is study and analyses (4) on the basis of academic, the reasonable method of bearing capacity is studied, educing the expression of resistance by introduce the factor of time (5) On the basis of degenerate model of bridge capacity,the limit state expression in damage state is educed ,introduce reliability theory into the evaluation and forecast of bridge.the capacity and life of a real Pre-stressed concrete bridge is evaluated and forecasted ,and a program based on the example are coded respectively. And finally, the direction of further research is briefly discussed.