To evaluate the fatigue behavior of prestressed concrete, bridges for instance, it is necessaryto determine the built in tendons’ fatigue strength. Therefore, prestressing steel samples(strands), obtained from an existing bridge built in 1957, were examined and tested by TUDortmund University, see [1, 2]. Additionally, similar prestressing steels were tested in comparableexperiments. As large experiments on prestressed concrete beams under cyclic load with smallstress range are very time-consuming and expensive, an early prediction of failure trend in theexperiment is desirable. Here, it is shown that a crack width function can be evolved dependenton the process of single wire failures. This process will differ for each experiment because of therandomness of single wire failure. Description of this uncertainty is the first step and is achievedby a predictive distribution for the counting process of wire failure. The second step is to includethese results into the model for the crack width process for which a nonlinear regression modelbased on a physically evolved function depending on the counting process is suitable. For bothmodeling steps, we present a Bayesian estimation and prediction procedure.
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