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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，通过两个典型的半潜器的算例，研究了基于极限强度分析的准静态极限载荷作用下半潜器可靠性评估程序包的适用性。本研究取得的成果概括如下：(1)介绍了系统的基本理论和系统概况。(2)通过梁结构和斜浪结构的算例验证了该系统的适用性。(3)通过引入重要系数作为损伤条件下的可靠性度量，讨论了一些设计变更对系统可靠性的影响。其次，给出了深水组合细长海洋结构物的极限强度和固有频率的概率分析方法，将其作为一个简单的塔架模型，将其塔架和平台分别替换为具有相同刚度和强度的梁柱。提出了一种考虑海洋生长和腐蚀引起的极端波浪荷载增加，以及腐蚀引起的刚度和耐久性退化的老化海洋结构物可靠性评估方法。进一步，利用概率灵敏度分析方法讨论了不确定性对固有频率的影响。最后，通过对450m拉索塔的数值算例，验证了所提方法的适用性。