EFFECT OF LOCAL JOINT FLEXIBILITY (LJF) IN STRUCTURAL ASSESSMENT OF AGEING JACKET OFFSHORE PLATFORM

Many fixed steel offshore platforms installed around the globe has exceeded or is
approaching the end of design life. In many operating areas, there is an attraction to
continue using these ageing facilities dues to continued production or as an adjoining
structure to facilitate a new field development or expansion. The structure of the Jacket
Type Offshore Platform (JTOP) are mainly connection of tubular members. To justify the
life extension of the fixed platforms, various integrity assessment techniques are often
used. One of the major techniques used is based on the phenomenon of Local Joint
Flexibility (LJF). Although LJF is well known in the offshore industry since the early
1980s, little proven data is available. A static structural analysis has been done using
ANSYS software to study the flexibility of the offshore tubular joint in a rigid state.
Deformation at the joint and stresses in the members of K -joint are investigated. The
joint is assumed to be in flexible condition which is subjected to tension and compression
to determine the deformation and stresses.