Active Duty Bridge Structure Dynamic Reliability Applications

We have gained great achievement in the study of confidence level of engineering structure. However many concrete bridges which were built before 1980 appear slump, because these bridges are not appraised reasonably in advanced. Structural reliability estimation and structural residual service life predication are some of the urgent problems need to be solved in the engineering field.Based on the dynamic reliability theory and the reliability estimation criteria, a new practical method is present in this paper, which will make the resolve of above problems available. The static reliability method is always adopted in the reliability analysis of structures, and it sometimes may lead to error according to the practical situation due to ignore of the resistance reduction with time. To overcome the shortage, in this paper, the time parameter "t" is introduced into the structural resistance and load model, and it makes the calculation of the dynamic reliability available. On the basis of the combination of the dynamic reliability theory and "Ideal critical structure", a quantitative calculation method is presented which can turn the estimation of structure reliability from qualitative analysis to quantitativecalculation. In the dynamic reliability theory, reliability index " β " is a function of the time parameter "t".So the time parameter "t" can be back calculated if "β" have been known. And if "β" is substituted by goal reliability index "β_m", theresidual service life of structures can be predicted. The dynamic reliability theory, the structural reliability estimation method and the structural residual service life prediction method mentioned above are applied to a simply supported beam bridge in this paper, and it is proved that the methods are practicable and feasible by living example.