Probability-based assessment of jacket-type offshore platforms by using incremental wave analysis

The age distribution for jacket-type offshore platforms in the Persian Gulf shows that relatively large numbers of installations have already passed their design life, which is around 25 years in that area. Despite the fact that reconstruction and repair of an existing installation are more economical than construction of a new one, assessment of existing jacket-type offshore platforms beyond their design life has been an issue for consideration. If a structure is intended to be used beyond its design life, a thorough control of the structural safety must be executed. Strictly speaking, desired extension of service life may create a need for requalification of a structure. Being events with extreme consequences, small frequency, and large uncertainty associated with their occurrence, extreme waves are among the most significant input to a jacket-type offshore platform. Hence, probabilistic methods are required for taking into account the safety compliance with regard to life extension of existing jacket structure.