摘要
区间估计法和贝叶斯估计法是国际标准ISO 2394:1998中根据试验结果推断抗力设计值的重要方法,但两者的推断结果并不一致,会导致设计人员在选用推断方法时产生疑虑。欧洲规范EN 1990:2002中仅选用了其中的贝叶斯估计法,但与一般的贝叶斯估计法不同,它未设置统计推断的置信水平,无法明确判定推断结果的信任程度。另外,对于抗力服从正态分布的情况,两个标准均未提供变异系数已知条件下抗力设计值的推断方法,难以更好地满足实际推断的需要。为解决这些问题,针对抗力服从正态分布和对数正态分布的情况,利用考虑可信水平的贝叶斯估计法提出新的抗力设计值的推断方法,该方法直接以未知参数的联合后验分布为依据,与推断依据有着更直接的联系,其推断公式和结果与区间估计法的完全一致;通过对比分析,揭示了国际标准ISO 2394:1998中贝叶斯估计法与区间估计法不一致的原因;同时,利用区间估计法提出了变异系数已知时抗力设计值的推断方法。新方法明确判定推断结果的信任程度,并可更好地满足实际推断的需要。
The interval and Bayesian estimation methods are important ones to infer structural resistance design value based on the outcome of the tests in International Standard ISO 2394: 1998,but the results obtained by these two methods are not consistent,which would lead to the confusion for designers to choose the methods. Although the Bayesian estimation method is only adopted in European Standard EN 1990: 2002,being different from the general Bayesian estimation method,it does not set confidence level for inferring,which makes it difficult to judge explicitly the degree of confidence on the results of inference. Moreover,on condition that the coefficient of variation is known when the resistance obeys the normal distribution,the methods for inferring structural resistance design values are not provided in these two standards,which could not meet the practical needs. In order to solve those problems,for the cases that the resistance obeys the normal distribution and log-normal distribution,a new Bayesian estimation method with explicit confidence level was developed for inferring structural resistance design values. Based on the joint posterior distribution of unknown parameters,the proposed method can give a result consistent with that by the interval estimation method. Through comparative analysis,it reveals the reason why the inference results obtained by the Bayesian and the interval estimation methods are different in International standard. On the basis of the interval estimation method,the methods for inferring structural resistance design values with the known coefficient of variation are put forward. The proposed method could help designers to judge the degree of confidence on the results of inference explicitly,which can satisfy the needs of practical inference.
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2015年第1期111-115,共5页
Journal of Building Structures
基金
国家自然科学基金项目(50678143
51278401)
关键词
结构抗力
抗力设计值
区间估计法
贝叶斯估计法
结构安全度
structural resistance
resistance design value
interval estimation method
Bayesian estimation method
structural safety
