基于能力谱法导管架平台抗震性能评估

针对现行海洋平台抗震规范无法考虑平台结构弹塑性抗震性能及地震失效机制问题,提出基于能力谱法海洋平台抗震性能评估方法,获得平台结构抗震性能及失效模式,解决强震作用下海洋平台结构弹/塑性抗震评估技术难题。基于规范推荐地震弹性设计谱,采用折减系数建立弹/塑性反应谱,结合渤海某导管架平台,采用能力谱法进行弹/塑性抗震性能评估。结果表明:能力谱法计算简便,对于以第1阶振型为主导地震响应的平台结构具有较好的精度;采用能力谱法评估地震惯性载荷时须考虑其高度效应,可采用倒三角或高度等效加载方式;桩基失效是平台结构地震作用下主要失效模式,平台抗震设计时应保证桩腿具有足够强度和入泥深度,避免强震作用下桩基失效而导致平台结构整体倾覆。

Seismic performance evaluation for jacket platform based on capacity spectrum method

As the current offshore platform seismic code cannot consider the inelastic seismic performance and the seismic failure mechanism, the seismic capacity evaluation method of offshore platform was proposed based on the capacity spectrum method. On this basis, the seismic performance and failure modes were obtained precisely, to solve the problem of evaluating the seismic behavior under strong earthquake. According to the design seismic spectrum, the inelastic reaction spectrum was established by reduction factor, and seismic evaluation of the jacket platform in Bohai sea of China was accomplished. The results show that the capacity spectrum method is suitable for offshore platform, because of easy calculation and creditable precision. The inverse triangle and high equivalence methods could be used to evaluate the earthquake force, so that the effects of altitude are considered. The pile foundation is one of the main causes leading to the platform to fail under seismic loads.When designing the seismic performance of a jacket platform, the strength and driving depth of the leg should be guaranteed, in order to avoid failure of pile foundation under strong earthquake which might lead to the platform to overturn.