Rules as Performance-Based

Design Criteria for Surface Ships

Funded by

Gulf Coast Region Maritime Technology Center

University of New Orleans

New Orleans, LA 70148

The objective of the study is to develop load and resistance factor design (LRFD) rules for ships by expanding on the recent accomplishments of the Carderock Division of the Naval Surface Warfare Center (CDNSWC) in this area that were led by Dr. Bilal M. Ayyub. The proposed outcomes of the project are LRFD criteria than can initially be used in parallel with currently used procedures, with the ultimate goal of phasing out the currently used procedures. The objective of the first year of this proposed study is to develop LRFD criteria for hull girder bending of surface ship structures that builds on previous work and accounts for both longitudinal and transverse bending and shear for both commercial and naval vessels. Future years (Year 2 and 3) will include development of LRFD criteria for unstiffened panels of surface ship structures, development of LRFD criteria for stiffened panels of surface ship structures, development of LRFD criteria for fatigue of surface ship structures, and integration of rules. The results of ongoing Ship Structures Committee studies will be considered as they relate to the tasks of the project. Also, the tasks of this project will be performed in coordination with engineers and researchers at the Navy. Attaining the general objectives of the study requires performing the following tasks:

(1) completing a state-of-the-art assessment and selection of reliability theories,

(2) estimation of variability in design and construction parameters, (3) selection of reliability assessment methods,

(4) estimation of variability in loads and load effects,

(5) modeling and analysis of uncertainty,

(6) implementation of theory and software development,

(7) reliability analysis and validation, and

(8) development of direct reliability-based design methods, and (9) development of load and resistance factor design (LRFD) criteria.