Optimal inspection and Repair Strategies for Structural Systems

A model for reliability-based repair and maintenance strategies of structural systems is described. The total expected costs in the lifetime of the structure are minimized with the number of inspections, the number and positions of the inspected points, the inspection efforts, the repair criteria and a design variable as optimization variables. A model for estimating the total expected costs for structural systems is given including the costs associated with the loss of individual structural members as well as the costs associated with the loss of at least one element of a particular group of structural members and the costs associated with the simultaneous loss of all members of a specific group of structural members. The approach is based on the pre-posteriori analysis from the classical decision theory. Special emphasis is given to the problem of selecting the number of points in the structure to be inspected and to select the location of the points to be inspected. It is shown how information obtained through inspections and through the periods of normal operating of the structure can be used to update the inspection and maintenance planning. Finally, a small example is given illustrating the suggested approach.