الفهرس 
LITERATURE REVIEWOnly 14 pages are availabe for public view
 |  | from | 210 |  |  |
| | | from | 210 | | |
Abstract
Circular hollow sections are most often found in heavy offshore
structures subjected to oscillating wave loads. The joints between
hollow sections are simple in form, but not simple when stress
distribution and design calculations are considered. Extensive studies
have been carried out on unstiffened joints, as a result of which their
behaviour under various types of loading have been well understood.
Methods of assessing their strengths have also been very well
developed. But little effort has been made to study in detail the
behavior of stiffened hollow section joints in intact conditions and the
• development of a methodology to assess their strengths. Information on
the strength and behavior of these joints in their intact conditions are
seldom available. They are useful in the development of guidelines for
the design of such joints in offshore structures and also in the
evaluation of the reduction in their strengths in case they are damaged
due to various causes.
The behaviour and strength of both stiffened and unstiffened
bollow section joints subjected to both axial compression force and in
plane bending moment have been studied theoretically in this work. A
nonlinear finite element model which allows for geometric nonlinearities
is constructed for the study using the nonlinear finite element
program ABAQUS. A pre-study is performed in order to verify the
developed numerical finite element model and its capability to
investigate the behaviour of the joints.
Large numbers of joints with different chord and branch
dimensions are selected, in order to draw complete Load-displacement
curves and to study the different failure modes. Different strengthening techniques are used which are: a) Strengthening using external gusset
plates, b) Strengthening using internal ring stiffeners, c) Strengthening
using collar plates and d) Strengthening using knife plates. Strength
equations are proposed for the case of using internal ring stiffeners.
Finally, comparison between different strengthening methods is
made to find the most applicable strengthening technique.