The objective was to obtain an accurate description of the ultimate and post-disaster strength of offshore platforms and other marine structures. This research will consist of:
(1) a critical review of current rules and methods for considering the tripping (buckling) behavior of symmetrical and asymmetrical stiffening elements;
(2) development of new solutions to fill any deficiencies of current analysis methods, especially at and beyond ultimate capacity;
(3) the testing of model specimens for the purpose of checking critical assumptions.
The project is expected to improve the reliability and accuracy of the design rules for the tripping mode and to prove a means for including this mode in the investigation of the ultimate and post- disaster of marine structures.
Completed. Comparison of the method developed for considering the effect of initial imperfections and the test results which assumed some levels of imperfection, pointed out a need for further work. The method was revised to include two additional coordinate functions in the deformation field so the interaction between the buckling modes of the stiffener and plate could be considered directly. The additional coordinate functions are constant curvature and sine squared. The results indicate that the effect of the stiffener web deformation appears to be relatively small. The method will be checked for accuracy of the new formulation and programmed for use in a parametric study.