OFFSHORE JACKET PLATFORMS – LRFD CODE CALIBRATION

A large number of the approximately 200
platforms in Malaysia have exceeded their design lives. New
platforms are being designed and installed. Any reduction in
the assessment of design loads or resistances of the structures
can translate into substantial savings in the design of the
platform. Further, this can lead to reductions in consumption
of precious resources like steel and reduce the carbon
footprint. LRFD provide a simple, safe and economically
efficient way of designing offshore platforms to different load
conditions and is able to incorporate regional practices in
design. LRFD considers the variability in parameters through
the use of safety factors. Safety factors are determined by
calibration and can be component based or system based. API
RP2A LRFD and ISO are such codes. Codes provide
standardization and optimal use of resources using calibration.
LRFD is apt for re-evaluation of old platforms for changes in
loads and changes in resistances due to deterioration. The aim
is to produce structures that have uniform and acceptable
reliability. This work examines how the load factors have been
calibrated in the different regions and the results are
presented. The lessons learned from these calibration efforts
are presented. Conclusions are drawn from these studies.