1 Reliability-Based Structural Design of Ships Using Load and Resistance Factor Design Approach

Future design rules for ship structures will be developed using reliability methods, and can be expressed in a special format such as the Load and Resistance Factor Design (LRFD) format. The main objective of this paper is to summarize the development methodology and results of reliability-based rules (i.e., LRFD rules) for ship structures that were performed for the U. S. Navy. The methodology for developing LRFD format for ship hull structural elements that was utilized in this paper consists of the following steps: (1) probabilistic characteristics of basic strength and load random variables that are used in structural design were analyzed. Values for these characteristics were recommended for reliability-based design purposes. They were determined based on the statistical analysis of data collected of these design parameters, on values recommended in other studies, or sometimes based on personal judgment. (2) Different load combinations were established and presented with combination and correlation factors, these combinations included the stillwater bending, wave-induced, and wave dynamic bending moments. The correlation between these different load components was accounted for and expressed in the form of correlation factors. (3) Limit states for these load combinations were established base