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Infrastructure systems cover an important role for economic activities and emergency response after a disaster, such as an earthquake. Within these systems, bridges represent a crucial component. However, they are often considered a weak link because of their vulnerability to hazards. Indeed, the structural damage of a bridge can create a disconnection in a transportation network or reduce its functionality. A probabilistic approach is the natural environment in which to analyze a complex network system and carry out risk/loss assessment estimations and decision-making processes. This problem presents various computational challenges and usually, sampling-based approaches are used to account for the uncertainty. In this contribution, a prioritization methodology is developed using the matrix-based system reliability (MSR) approach. This method is capable of delivering component failure probabilities and estimating the probabilities of complex system events with parameters sensitivities through efficient matrix calculations.

In this contribution we discuss a new framework for the analysis of the bearing capacity of masonry structures, modeled as assemblies of rigid blocks, which allows to correctly take into account the influence of foundation settlements. The crack pattern at failure and the associated mechanism are described by means of a proper treatment of unilateral contact constraints arising between contiguous rigid blocks, in which the structure is partitioned. We extend two classic variational formulations for the Signorini problem, namely the minimum of the total potential energy and a boundary complementary formulation where the unknowns are contact pressures only, to the case of the contact between multiple rigid no-tension masonry bodies, for which Heyman hypotheses are satisfied. The discretization of these two variational formulations leads to two dual linear programming problems. While the first one is classical and maximizes the work of external loads, the second one minimizes the work of constraint reactions for the assigned displacements and it appears new in the literature.