ABSTRACT
In structural design codes, reliability-based load and resistance factor design (LRFD) is commonly used. For almost all existing reliability methods utilized to evaluate load and resistance factors, it is assumed that the probability distribution of the fundamental random variables is known. However, in engineering practice, owing to the unavailability of statistical evidence, the probability distribution of some fundamental random variables is typically unknown. This chapter illustrates the method of moments for conducting LRFD under unknown probability distribution random variables. The method of moments uses the first few statistical moments of the fundamental random variables (i.e., mean, standard deviation, skewness, kurtosis) to evaluate load and resistance factors, such that the LRFD can be performed with random variables involving unknown distributions, and there is no need to iteratively calculate derivatives or design points. Therefore, the method of moments is convenient and effective in actual engineering for determining LRFD.
