Multi-objective optimization for bridge retrofit to address earthquake hazards

Abstract

Protecting infrastructures against natural hazards is a pressing national and international problem. Given the current budgetary climate, the ability to determine the best mitigation strategies with highly constrained budgets is essential. This papers describes a set of computationally efficient techniques to determine optimal infrastructure investment strategies, given multiple user objectives, that are consistent with an underlying earthquake hazard. These techniques include: optimization methods for developing representative events to characterize the hazard and the post-event condition of infrastructure components, a simulation model to characterize post-event infrastructure performance relative to multiple user objectives, and a multi-objective optimization algorithm for determining protection strategies. They are demonstrated using a case study of the highway network in Memphis, Tennessee.

Multi-layered security investment optimization using a simulation embedded within a genetic algorithm

“…Brown, Jones, Nozick, and Xu This research is also related to the extensive literature on attacker-defender models. Conceptually, our model is similar to models suggested by Romero et al (2012) and Brown et al (2013) among others. Our model is similarly focused on investment planning to thwart attacks, however, our model of intruder behavior focuses on the probability of interruption whereas these models focus on satisfying demands for services.…”

“…A related variable-rate mutation strategy employed in Brown et al (2013) is used to counter the tendency for crossover to produce homogenous populations as described in Sait (1999). Mutations are based on the level of consistency amongst security investment strategies across the population of solutions.…”

A modeling framework for investment planning in interdependent infrastructures in multi-hazard environments.

“…The hazards in this region include the NMSZ seismic threat to the roadway bridges and an act of terrorism against the hospitals. This optimization is an extension of the multi-objective, 2-stage stochastic problem described in Brown, et al (2013). In that paper, there were two interdependent infrastructures (the Memphis roadway network with bridges and the hospital system), but only a single hazard (seismic).…”

“…For the seismic hazard, we use the approach as described in Brown, et al (2013), which involves a single run of the optimization to determine the Pareto points that consider the total travel time, hospital connectivity, and seismic portion of the cost. For the terrorist hazard, we can execute a separate optimization that determines Pareto points for terrorism mitigation costs and terrorism hospital connectivity objectives.…”

“…For the seismic hazard, we use the approach as described in Brown, et al (2013), which involves conducting a single run of the optimization to determine the Pareto points that depend on the total travel time, hospital connectivity, and the seismic portion of the cost. The high-level solution procedure can be summarized in the following points and Figure 4.…”