Cost-benefit analysis for the optimal rehabilitation of deteriorating structures

A cost-benefit analysis for planning rehabilitation efforts of deteriorating structures is proposed, which takes into account all life-cycle costs, such as construction, failure, inspection and state-dependent rehabilitation costs, as well as state- or time-dependent benefit rates. Rehabilitations can take place anytime throughout the lifetime and are optimized by maximizing the expected net present benefit rate. This approach not only allows to determine optimal sequence of rehabilitation times and rehabilitation levels, but allows also to determine optimal lifetimes and acceptable failure rates. Numerical examples demonstrate that proper planning of rehabilitations allows to extend the lifetime of a structure – as long as the expected costs for such efforts outweigh the expected future benefit. If this is not the case, then, indeed, the structure is obsolete and alternatives have to be evaluated.