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Practical Method of Reliability-based Assessment and Design of a Structure with Long Service Life

长寿命结构可靠性评估与设计实用方法

基本信息

批准号：
15560491
负责人：
MORI Yasuhiro
金额：
$ 1.86万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560491/
关键词：
Structural Reliability Limit State Design Long Service Live Load and Resistance Factors Load Combination Stochastic Process Structural Degradation Inspection and Maintenance 基準期間

项目摘要

Because of their enormous numbers, extending the service life of building structures designed by an ordinary structural engineer is one of the most important factors for achieving sustainable society. However, the length of service life of a structure is not considered explicitly in current design provisions. In reliability-based limit state design, the performance level of a structure can be controlled by differentiating load and resistance factors considering the length of service and the variability in load intensity and structural capacity. A practical method for evaluating load and resistance factors is proposed in "Recommendation for Limit State Design of Buildings" by AIJ. However, because of the simple approximation of non-lognormal random variables to lognormal, the reference period is fixed as 50 years, and accordingly, the recommendation cannot be properly used for designing a structure with longer service life.Also a structure could deteriorate due to environmental stressors and repeated loading. Such deterioration may not be a problem for a structure with short service live, but should be considered for a structure with long service life. However, again no existing design code considers the deterioration of a structural performance during its service life.For the degradation of structural performance, the investigator has introduced the concept of a resistance factor with which a time-dependent reliability problem can be approximated as a time-independent one. In this research, a practical formula for a resistance reduction factor is proposed classifying the cumulative distribution functions according to the classification of parent distributions of extreme value distributions. Also, an improved simple approximation method, which can consider the service life of a structure, for load and resistance factors is proposed using AFOSM directly. The accuracy and its applicability are investigated using numerical examples.

由于其数量巨大，延长普通结构工程师设计的建筑结构的使用寿命是实现可持续社会的最重要因素之一。然而，在现行的设计规定中，没有明确考虑结构的使用寿命长度。在基于可靠性的极限状态设计中，结构的性能水平可以通过区分荷载和抗力系数来控制，同时考虑使用寿命以及荷载强度和结构承载力的变化。AIJ的《建筑物极限状态设计建议书》提出了一种实用的荷载和抗力系数计算方法。然而，由于非对数正态随机变量简单地近似于对数正态，参考期固定为50年，因此，该建议不能正确地用于设计具有更长使用寿命的结构，并且结构可能由于环境应力和重复载荷而劣化。对于使用寿命较短的结构来说，这种退化可能不是问题，但对于使用寿命较长的结构来说，应该考虑这种退化。然而，现有的设计规范也没有考虑结构在使用寿命期间的性能退化。对于结构性能退化，研究者引入了抗力系数的概念，利用抗力系数可以将时变可靠性问题近似为时变可靠性问题。在这项研究中，提出了一个实用的公式阻力减少因子的分类的累积分布函数根据父分布的极值分布。同时，提出了一种能考虑结构使用寿命的改进的AFOSM载荷和抗力系数的简单近似方法。数值算例验证了该方法的精度和适用性。