Strength of ring-stiffened tubular T-joints in offshore structures—: a numerical parametric study

Lee, M.M.K and Llewelyn-Parry, A. Llewelyn (1999) Strength of ring-stiffened tubular T-joints in offshore structures—: a numerical parametric study. Journal of Constructional Steel Research, 51 (3), 239-264. (doi:10.1016/S0143-974X(99)00027-9).

Abstract

Although not commonly used in modern design, ring-stiffeners were extensively used to enhance the strength of tubular joints found in older offshore steel jacket structures. No detailed guidance on the determination of strength of ring-stiffened joints can be found in any major offshore code. There is therefore a need for research for the purposes of structural assessment when platforms are upgraded or modified. This paper presents the results of a detailed parametric study of the static strength of axially loaded tubular T-joints with internal ring-stiffeners. The study, carried out using non-linear finite elements, first established the accuracy and the validity of the numerical procedure by comparing with test results available in literature. The validated procedure was then used to investigate the effects of the various geometric parameters that influence the strength of the stiffened joints and of the stiffeners. In total, 42 stiffened joints, some included multiple stiffeners, were analysed. The results confirm findings from previous experimental work that stiffened joints fail at deformation levels similar to those of their unstiffened counterparts and are therefore able to maintain their ductility. Observations on the development of plastic zones in the stiffeners show that the failure mechanism is the formation of plastic hinges from bending, rather than failure through vertical shear, as previous research suggested.

This record has no associated files available for download.

Contributors

Download statistics