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Developmental Study on Structural Reliability Assessment Systems of Marine Structures

海洋结构物结构可靠性评估体系的发展研究

基本信息

批准号：
01850095
负责人：
OKADA Hiroo
金额：
$ 4.16万
依托单位：
University of Osaka Prefecture
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B).
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01850095/
关键词：
Marine frame structure Ultimate strength Dynamical effect Structural reliability Dominant failure mode Failure probability Importance factor Structural synthesis 立体骨組モデル経年変化

项目摘要

1. At first, applicabilities of the program package developed for reliability assessment of marine structures are investigated through numerical examples for two typical semi-submersibles, which are modeled as spatial frames and subjected to quasi-static extreme loads based on ultimate strength analysis. Results obtained in this study are summarized as follows :(1) The underlying theory and the system's overview are provided. (2) The applicability of the system is demonstrated through the numerical examples for structures under beam and oblique seas (3) Effects of some design alterations on system reliability are also discussed by introducing importance factors as reliability measures under a damaged condition.2. Next, methods are presented for the probabilistic analysis on the ultimate strength and the natural frequencies of composite and slender offshore structures for deep water, which are treated as a simple tower model by replacing its tower frameworks and platform with the beam-columns with equivalent stiffness and strength, respectively. A method is also presented for reliability assessment of aged marine structures considering increase of extreme wave loads due to marine growth and corrosion, and deterioration of rigidity and resistance due to corrosion. Further, the effect of uncertainty on the natural frequencies is discussed by using a probabilistic sensitivity analysis method. Finally, the applicability of the proposed methods is demonstrated through the numerical example for a 450m guyed tower.

1.首先，以两个典型的半潜式平台为算例，对所开发的海洋结构物可靠性评估程序的适用性进行了研究。主要研究成果如下：（1）介绍了系统的基本理论和系统的概况。(2)通过梁式和斜浪下结构的算例，验证了该体系的适用性。（3）通过引入重要性因子作为损伤条件下的可靠度度量，讨论了设计变更对体系可靠度的影响。其次，将组合结构和细长结构作为一个简单的塔架模型，分别用刚度和强度等效的梁柱代替塔架和平台，给出了其极限强度和固有频率的概率分析方法。考虑到海洋生物和腐蚀引起的极端波浪载荷的增加以及腐蚀引起的刚度和抗力的劣化，提出了一种老化海洋结构物可靠性评估的方法。进一步，利用概率灵敏度分析方法讨论了不确定性对结构固有频率的影响。最后，通过一个450米拉线塔的数值算例，验证了所提方法的适用性。