Optimal resource allocation for seismic reliability upgrading of existing structures and lifeline networks

A campaign of preventive measures aimed at upgrading an ensemble of buildings or other constructed facilities, whose seismic reliability is considered unsatisfactory, faces two difficulties: the limitation of the available resources, that must be therefore used in an optimized way, and the multiplicity of the aspects that should be taken into account in their allocation (direct and indirect economic losses, number of endangered persons, severance of a lifeline network, etc.). This lecture will first discuss in general terms how to approach these problems (in particular how to describe the seismic vulnerability in a way that can be used in such multiobjective optimization), then will present examples of optimal allocation of the available resources to seismic upgrading of existing structures and lifelines. The examples refer to masonry buildings, whose damages can be summed with each other to obtain the total damage of the ensemble, and to highway networks, i.e., systems whose critical elements are reinforced concrete bridges. Two objective functions are considered for each example and realistic values are attributed to the relevant parameters, so that the examples confirm the feasibility and applicability of the optimal allocation.