Study Of Effect On Reliability Of Offshore Platform By Seismic Action

With the rapid growth of China's economic and the increasing demand of oil resource, offshore oil and gas fields and offshore platforms will enter a new period of development. The several strong earthquakes worldwide recently imply that the earth have enter a period of earthquake-prone. And our country's sea areas are also in the circum-pacific seismic belt. There are still many problems in the study of reliability of offshore platform need to be solved.In the process of modeling of jacket offshore platform, pipe59 element is used to simulate the pipe in water, for which we can get wave load and ocean current load more exactly. According to the API specification, we get the most unfavorable processing conditions. To analysize the responses of jacket platform under the three static load conditions, the rules of maximum stress and maximum displacement can be got. Based on the geological conditions of the platform seat, to use the Taft seismic wave and do dynamic analysis of offshore platform by transient dynamical analysis in the ANSYS. Finally, summarize the variation of responses with time.According to the analysis of offshore platform's responses and definitions of serviceability limit state and ultimate limit state, significant failure mode can be simplified to three forms. Because of the PDS in ANSYS do not have typeâ… extreme value distribution, we should deal with the distribution of environmental loads. Calculate the reliability of offshore platform under the effect of earthquake and draw a conclusion that earthquake is controlled factors of offshore platform's reliability. Through the sensitivity analysis, obtain the input variables which have more obvious impact on reliability under every load conditions.