ABSTRACT
ABSTRACT The residual structural lifetime of concrete bridges is often limited by fatigue of the pre-stressing steel. In practice Miner's rule based on load frequencies and stress amplitudes is usually employed. Thereby, various parameters must be accounted for whereof a few are actually relevant.
Structural monitoring is valuable to increase the accuracy of lifetime predictions, but usually experts choose the right parameters on experience only. A more objective assessment can be reached by sensitivity analysis. Powerful are Sobol's variance-based indices. They quantify the influence of a single parameter's variance on the model's total variance and account for interactions in non-linear models, too.
Exemplified on a reference structure sensitivity indices are determined meanwhile specific characteristics like the non-linear behavior of concrete after cracking are consequently considered. In this case the key elements of lifetime prediction to be monitored turn out to be the time-dependent losses of pre-stress and the traffic loads.
