2006 Volume 5 Issue 1 Pages 129-136
The objectives of the present paper are to investigate the applicable range of the third-moment method for structural reliability and to suggest a simple third-moment method for practical application in engineering. The applicable range of the second-moment method is also given. The applicable range of the third-moment method is obtained through investigation of the differences among several third-moment methods. Within the applicable range, it is found that the simple reliability index has a good agreement with the original one, and it is therefore suggested as a simple third-moment reliability index. Since only the first three central moments of the performance functions are used, and since it is unnecessary to know the probability distribution of the basic random variables, the present method should be practical in engineering. In order to investigate the efficiency of the proposed method, several examples are examined under different conditions.