Safety Trend Analysis: Construction-Year and Age Dependency in Technical Systems

摘要

A methodology for statistically analysing rare failure events is proposed that may allow an improved evaluation of the longer term progress of the safety performance during the continuing evolution of a technology. The actuarial data base consists of the record of major failures, especially construction year and age for the failed units, as well as construction rate and size of population. The state-of-the-art of safety is quantified by the failures up to the same age, that requires an augmentation of the actuarial information. A refined (average) age variation of the failure occurrence that is formally derived from the data is employed for the augmentation of the actual failure information. The application of this method is illustrated for the evaluation of the progress of the safety of large embankment dams in the U.S. for the period 1850 through 1980. (ERA citation 09:023201)