RANDOM TIME DOMAIN ANALYSIS OF AGING JACKET PLATFORMS IN PERSIAN GULF

Offshore platforms are in a rough environmental condition and therefore structural damages are undeniable for the aging platforms. These structural damages, which are the results of fatigue, corrosion and other unavoidable events, reduce the stiffness of the structure. When the stiffness of the structure decrease, the dynamic response of the structure is becoming important and must be investigated. In this research, dynamic behavior of an existing jacket platform in the Persian Gulf under extreme environmental condition is investigated by using random time domain simulation method to reach a reliable value for DAF in the extreme condition. Fifteen, 1-hour storm, simulations for the water surface elevation is produced to capture the statistical properties of extreme sea condition. Time series of base shear and overturning moment are derived from both dynamic and static responses. By calculating the maximum DAF from each simulations and fitting the collected data to Weibull distribution, the Most Probable Maximum Extreme (MPME) value for the DAF is achieved. Results show that DAF for this type platform is a noticeable value and should be included in any analyses.