Evaluation of Seismic Behavior of Fixed Offshore Platforms with Endurance Time Method

Evaluation of seismic behavior of offshore platforms is one of the important design steps in seismic regions. Nevertheless, because of complication and time cost of these methods, engineers usually do not study them deeply. Endurance Time (ET) method is a good solution for this problem. In this method, with acceptance of a reasonable region of errors, the time of analysis can be reduced considerably. Besides with one ET analysis, the behavior of structure can be evaluated in different seismic levels. In this paper, the ET and other usual methods in standards are introduced and then the seismic behavior of three platforms is compared with ET and response spectrum method. In this comparison, the acceleration function which is generated base on Iranian cod (2800 standard), is used and the differences are considered in relation to spectral analysis of 2800 standard. The results show appropriate conformity between two methods.