Multi-objective optimal allocation of resources for preventive interventions on bridges

In order to reduce the risk of disruption by an earthquake (or any other disaster), preventive interventions on existing facilities are necessary, but often hindered by the limitation of the available economic resources; therefore, the optimal allocation of resources becomes a key point for the effectiveness of any risk-reduction program. In a series of recent papers a procedure has been developed for optimal allocation of limited resources in preventive interventions aimed at increasing the seismic reliability of highway networks with respect to several alternative objectives (connectiveness of the network, traffic capacity, etc.). In the present paper, the procedure is extended in order to take account of several possible objectives in a multiobjective optimization procedure. To explain and illustrate the procedure, an example of optimal allocation in a specific network is developed in detail: the vulnerable elements of the network are identified with reinforced concrete bridges located in the nodes of the network. The results obtained are compared and discussed.