Abstract:

Based on the statistical analysis of a lot of domestic test data on the strengths of normal-strength concrete and steel bars after high-temperature treatment, the mean values and variances of the relative residual strengths of the above-mentioned materials treated at different temperatures are obtained, and the corresponding normal distribution test is carried out. Afterwards, the quantitative relationships between the temperature and the mean value as well as the value with a guarantee rate of 95% are modeled. The results indicate that the relative residual compressive strength of concrete, the relative residual yield strength of hot-rolled bar and the relative residual ultimate strength of prestressed reinforcement all accord well with the normal distribution, and that, with their high accuracy, the proposed quantitative models provide the basis for the reliability evaluation of reinforced concrete structures after fire.

Key words: high-temperature treatment, concrete, steel bar, strength, statistical analysis