Renewal Models for Optimal Life-Cycle Cost of Aging Civil Infrastructures

Civil infra-structures such as roads, bridges, life lines, etc. can fail upon extreme loading requiring replacement, must be replaced after severe deterioration and can become obsolete which usually also requires replacement. Considering the scarcity of resources, especially public money, they should be cost-optimal including initial planning and erection cost, maintenance cost and, possibly, failure, demolition and reconstruction cost. Since time is involved these cost must be discounted appropriately. Here we propose a well-known renewal model and modify it appropriately to cover the majority of cases met in practice, especially extreme value failure, obsolescence and aging.