工程结构作用极值分析方法研究

由于对工程结构所承受的各类作用进行极值分析,是确定作用的设计值以及服役结构的作用评估值的重要依据,针对目前的作用极值分析方法,主要在3个方面展开了探讨,即作用的截口分布的估计、最大值分布的估计以及估计结果的不确定性的评估等,发现了这些环节所存在的一些问题和缺陷：作用截口分布的估计缺乏客观性,而且估计的准确性不足;采用随机过程模型计算作用的最大值分布是不合适的;在极值的分析中缺乏对于不确定性的必要的估计,同时也存在一些细节上的欠妥之处。最后针对主要的问题提出了建议：采用阈值模型估计作用的底分布,采用点过程模型直接估计最大值的广义极值分布,并且考虑估计的不确定性选择适当的估计。

Research on Extreme Value Analysis Method of Actions on Engineering Structures

The extreme value analysis of various actions on structures was the basis of the determination of the actions design values for new structures and actions assessment values for service structures. These methods about analysis of extreme value of actions were discussed on three aspects which were the estimation of truncated distribution of actions, the estimation of maximum value distribution of actions as well as the assessment of uncertainty of estimation result. Limitations and deficiency were found in all these aspacts：firstly, the fitting method for base distribution of actions lacked in objectivity and was inaccurate; secondly, it was not appropriate to analyze the maximum value distribution of actions using stochastic process model; thirdly, the uncertainty in the estimation of extreme value was neglected, and some imperfections were pointed out in details. Finally, suggestions to the main problems were presented, which estimated the base distribution of actions using threshold model estimated the generalized extreme value distribution of maximum value of actions directly using the point process model, and considered the uncertainty of estimations to select the appropriate one.