Abstract
Lifetime cost minimization is the optimal criterion for planning of inspection, repair and maintenance of structures. However, most of the probabilities and the cost items referred in the cost analysis generally contain inevitable uncertainties in actual cases. The appropriateness of inspection planning may be lost by several errors induced by such uncertainties.
In this study, a cost minimization method with constraint of reliability is developed in order to obtain a stable inspection planning against the estimation errors of the parameters. In the analysis, the lifetime cost optimization is carried out under the constraint that the failure probabilities of the members are controlled below the respective target values allowed for the members. First, initial target failure probabilities are assumed for each member. Then the robustness of the inspection planning is investigated by adjusting the parameters within the range of uncertainties. The initial values of the target failure probabilities are altered until an acceptable result be obtained.
Applicability of the proposed method is examined for a structure with several uncertain parameters. A sequential cost minimization method developed in the previous paper is employed to optimize the lifetime cost. It is made clear that the stability of the lifetime cost is maintained without losing the benefit of the cost minimization method by the use of this approach.
