Determination of Seismic Fortification Level of Offshore Platforms in China

摘要

The current seismic design code commonly used in the world is RP2A-WSD compiled by American Petroleum Institute, there is still no specific seismic design code for offshore platforms in China. In this paper, a brief introduction of RP2A-WSD code is given at first, and the comparison between the seismic fortification levels of RP2A-WSD and that of Chinese GB17503-1998 and GB50011-2001 suggests that the levels of Chinese Codes are overestimated. Secondly, the seismic damages and anti-seismic design requirements of offshore platforms are discussed in view of their structural characteristics. On the basis of the analysis above, summing up the factors, such as the seismic activity in the waters of China, structural characteristics of offshore platform,seismic design goal, and the seismic fortification experiences of related engineering, we recommend that the seismic fortification level of strength design take a return period of 200 years, and that of deformation design take a return period of 3000 years respectively for offshore platforms in China. Finally, the comparison with other Chinese Codes of related industries shows that the recommended fortification level is safe and rational.