Stochastic FEM-based validation of LRFD

Stochastic finite-element based reliability analysis is used to examine the performance of the load and resistance factor design (LRFD) method for steel structures. The reliabilities of members in actual configurations are estimated for both strength and serviceability limit states using the proposed method and compared with the target reliabilities used to derive the LRFD specifications. The dependence of the reliability of a member in an actual structure on the statistical properties of other members, the location of the member in the overall configuration, and the statistical correlations between the various random variables is investigated. The LRFD specifications, which are based on reliability analyses of isolated simple structural elements, are found to result in a conservative design of members in complicated structures, especially when the design is governed by serviceability criteria.