In this article, wave endurance time (WET) is addressed as an applicable method for performance-based assessment of fixed offshore structures under extreme waves. In this method, inspired by the endurance time method in the field of earthquake engineering, artificial wave records called wave functions are designed so that their excitations gradually increase with time. Therefore, the main advantage of the proposed method is that it can assess the structural performance under various wave load conditions through a single time-history analysis. Moreover, the reliability of structures can be evaluated on the basis of the time that the structural response is still acceptable. In this study, generation of these artificial records and their application to assessment finite element model of a fixed offshore structure are described based on the extreme waves of the Persian Gulf. In order to consider the accuracy of this method in estimation of the structural response, finite element method is utilised to compare the results of the WET method with the results of typical 3-hour random records. It is concluded that WET is a computationally attractive method to estimate the structural response with reasonable accuracy.
