地震作用下大型升船机结构的时变动力可靠度

TIME DEPENDENT DYNAMIC RELIABILITY OF LARGE-SCALE SHIP-LIFTING TOWER STRUCTURE UNDER A SEISMIC LOAD

利用三维有限元方法对三峡升船机塔柱结构的动力学特性及随机地震响应进行了计算分析,结果表明塔柱结构柔度较大,其顶部节点随机地震位移响应为中宽带过程。在此基础上,采用首次超越破坏机制,以塔柱结构顶部典型位置的位移限值为可靠度界限,对设计地震烈度下升船机塔柱结构的时变动力可靠度进行了计算分析,得到了塔柱结构设计基准期内的时变动力可靠度,并讨论了可靠度界限值的随机性对结构抗震时变可靠度计算结果的影响,建议升船机结构抗震可靠度计算模型采用Markov过程假定。该文可为升船机结构设计及安全运行提供必要的参考。

The dynamic characteristics and the random seismic response of Three Gorges＇ ship-lifting tower structure were investigated by using 3-D FEM model. The dynamic characteristics results show that the tower structure has large flexibility. The random seismic response is found to be a median-wide band process. Based on the first excursion probability mechanism, the time dependent dynamic reliability of the ship-lifting tower structure under designed earthquake intensity was calculated by assuming the reliability level to be the displacement limit of the structural typical position on the top floor of the tower. The time dependent dynamic reliability of the tower structure in the design base period was obtained. The effects of the definite level and the random level on the time dependent dynamic reliability under a seismic load were also discussed. The model based on Markov hypothesis is advised for aseismic reliability analysis of ship-lifting tower structures. It could provide engineering information for the design and safe service of ship-lifting structures.