Structural Reliability Analysis Based On The Fuzzy-Random Probabilistic Theory

The theory of reliability is more advanced and more reasonable than the method of single safe factor. Reliability of structure is related not only to certain and uncertain influence factors, but also to fuzzy uncertain of destroy rule. Considering these uncertain influence factors, meaning of subject function of structural damage has been discussed and analyzed, fuzzy reliability index formulas of structure have been presented using theory of structural reliability and fuzzy mathematics, and establishes influence factor of index of fuzzy-reliability-the effects of variation coefficient of structural resistibility tolerance of load effect and tolerance of structural resistibility return model in order to assay and predict index of fuzzy-reliability in dR+dS destroying tolerance. Checking computations have been made with pre-stress hollow core slab as an example, and the effects of variation coefficient of structural resistibility, tolerance of load effect and tolerance of structural resistibility, etc, are analyzed. Several conclusions which have been obtained are in agreement with real practice. The result of confidence level calculated by common method only is a mean value, and there may be tremendous difference between the mean confidence levels and the actual confidence levels to building structure, and it's difficult to determine the distribution and the parameter of small sample stress and intensity at the same time. These cause the large discreteness of structural actual confidence levels. So it isnecessary to discuss the calculation method for the confidence interval of fuzzy confidence level under the given degree of confidence. In this paper, the methods of determination on confidence interval of common model building structure fuzzy confidence level are given. Popularize the theory of traditional random reliability to the theory of fuzzy-random reliability; Two examples illustrate the process of calculating the fuzzy-random reliability.The analytic result of this paper clarifies: the structural fuzzy-random index, consider not only random-uncertainty of every variable, but also fuzzy-uncertainty of destroy rule in order to make analysis-calculation all-sided in reason.It is feasible to substitute the theory of fuzzy-random reliability for that of traditional random reliability; It is more feasible and coincident practice of engineering to substitute the interval value of fuzzy-random reliability index for certain value.Finally, the author tables proposal to some concerned problems needing to be studied farther.