PADEYE STRUCTURE ANALYSIS ON THE LIFTING PROCESS
OF FOUR LEGS JACKET WITH DYNAMIC APPROACH
Name
: Henny Gusti Pramita
NRP
: 4309100007
Department
: Teknik Kelautan –FTK ITS
Supervisors
: Ir. Handayanu, M.Sc, Ph.D
Yoyok Setyo H., S.T., M.T
ABSTRACT
Three major operations during jacket platform installation is load-out, launching,
and upending. Loadout consists of several methods. One of the methods is lifting.
There are two analysis for this four legs jacket lifting, they are static and dynamic
analysis. Dynamic analysis is done to determine the response of jacket structure
due to the influence of dynamic loads such as wind gusts. Under static analysis
condition, jacket structure has 0.849 in unity check with factor 1.5 on the member
84 and this structure failed when the factor is 2 and has 1.314 in unity check.
Dynamic response of the structure is in the form of swing phenomena. This
phenomenon occurs due to the motion module experienced during the lifting
process. And this motion caused by wind. Added force on the structure is 4091,97
KN ; 4633,42KN; and 4207,52 KN. That force occurs when the wind velocity is
5.13 m/s (local wind velocity), 20 knots (GL Noble Denton), and when the wind
velocity is 7.4 m/s (Beaufort scale). Structural response calculation results are in
accordance with the API RP 2A-WSD and DNV Pt2 Ch5 Lifting (1996) statement
on the Dynamic Amplification Factor. That results are still in the provision of
these factor. Local analysis of the padeye structure performed using software and
the equivalent stress obtained from this analysis is 26.311 MPa, with allowable
stress for steel A36 is 165 MPa. Because the equivalent stress is less that the
allowable stress, this padeye structure can be safely operated.
Keyword : Loadout, Lifting, Jacket, Padeye.
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