Cost benefit based maintenance optimization for deteriorating structures In recent years increasingly consideration has been given to the lifetime extension of existing structures. This is based on the fact that a growing percentage of civil infrastructure as well as buildings is threatened by obsolescence and that due to simple monetary reasons this can no longer be countered by simply re building everything anew. Hence maintenance interventions are required which allow partial or complete structural rehabilitation. However maintenance interventions have to be economically reasonable that is maintenance expenditures have to be outweighed by expected future benefits. Is this not the case then indeed the structure is obsolete at least in its current functional economic technical or social configuration and innovative alternatives have to be evaluated.