The Resistance Probability Analysis Of Corroded PC Beam Based On Small Sample And Interval Data

In the existing prestressed concrete bridge in our country, Corroded bridge PC various unfavorable factors in the increase year by year, especially based on the chloride salt environment. This paper considers in chloride environment, due to corrosion of prestressed steel strand resulting in beam attenuation resistance, serious impact on the safety of the bridge in service. In this paper, on the basis of this, according to the likelihood function and the maximum entropy theory, established the uncertainty of PC bridge resistance caused by two kinds of data sources of degradation analysis method. This paper is mainly on the research from the following aspects:(1) Introduced in the chloride environment due to corrosion of steel strands leads to the present research situation of PC bridge resistance degradation, and the analysis of the current domestic and foreign existing prestressed concrete bridge structural problems facing,and the strand of corrosion factors were analyzed and discussed.(2) In the service of PC bridge, because of the influence of subjective factors and objective factors such as the condition, can produce all kinds of uncertainty. This paper introduces the sources of uncertainty in the process of bridge in service, how these uncertainties were isolated and uncertainty quantification done related research. In this paper, using the likelihood function and the maximum entropy theory to process caused by the two sources of data uncertainty, this ratio does not consider the uncertainty(in this case is calculated using the maximum likelihood estimation method) is more reliable.(3) Because the steel strand is different in chemical composition and organization structure, making the steel strand corrosion in unfavourable environments and ordinary reinforcing steel bar is different. The main work is as follows: First, the general form of the reinforcement and prestressing strand corrosion under adverse environmental comparative analysis; the shape of post-strand corrosion pits were discussed and analyzed and summarized the pits depth, length and width of the distribution. Finally, the method seems to discuss likelihood function based on the maximum depth and maximum width pits small sample data uncertainty conditions PDF.(4) Under unfavorable conditions, combined carrying capacity model has been derived after scholars strand corrosion and flexural capacity of the model introduced after deformation compatibility coefficient can be corrosive PC Beams capacity model in the calculation of PC beams. Then with a bending real bridge as an example, analyzes the influence on the resistance uncertainty in the two categories of data condition. The results show that: the likelihood function and maximum entropy theory to construct a variable probability density function, can reduce subjective uncertainty, the results thus obtained closer to the real situation.