Probability Distribution Model for Cross-Sectional Area of Corroded Reinforcing Steel Bars: Fid-Bau Portal

Probability Distribution Model for Cross-Sectional Area of Corroded Reinforcing Steel Bars

Zhang, Weiping / Zhou, Binbin / Gu, Xianglin / Dai, Hongchao

This paper presents the development of a probabilistic model for the cross-sectional area of corroded reinforcing steel bars (rebars), in order to assess the time-dependent reliability of corroded reinforced concrete (RC) structures. The indicator $R$ , which is the ratio of the average to the minimum cross-sectional areas of corroded rebars, was adopted to quantify the longitudinal variation of the cross-sectional area. By using a three-dimensional laser scanning technique, the areas of the discrete cross-sections were evaluated along the length of a rebar at intervals of 1 mm. The statistical results showed that $R$ could be characterized by the Gumbel distribution. Both the location parameter and the scale parameter for the probability distribution of $R$ increased linearly with increases in the corrosion degree and were dependent on the element length and the diameter of the corroded rebar. The results of a time-dependent reliability analysis of corroded RC beams demonstrated that an element length of 150 mm should be chosen for reliability assessment and that larger diameter rebars should be chosen for structural design when the reduction of load bearing capacity caused by corrosion of rebars needs to be considered.