Risk-Based Decision Making for Sustainable and Resilient Infrastructure Systems

The development of infrastructure systems that are sustainable and resilient is a challenging task that involves a broad range of performance indicators over the system lifecycle that affect system functionality and recovery. Sustainability indicators address economic, social, and environmental performance metrics and resilient indicators address strength, functionality, and recovery-time metrics following a hazard event. Sustainable systems consider environmental impact and conservation of nonrenewable resources over the life of the system. Resilient systems consider performance levels relative to potential damage levels and recovery times from events. Both concepts address adequate system performance and lifecycle costs, but put a different emphasis on other indicators. Numerous sources of uncertainties associated with the lifecycle performance of infrastructure systems require the use of a risk-informed decision-making approach to properly account for uncertainties and to identify cost-effective strategies to manage risk. A framework for risk-informed decision making for the lifecycle performance of infrastructure facilities that includes consideration of sustainability and resilience is presented. Separate examples are provided for the same highway bridge deck system to illustrate sustainable and resilient performance objectives with the design and rehabilitation of highway bridge decks. The sustainability assessment considers the effect of corrosion degradation mechanisms on lifecycle costs, environmental impact (CO2 and waste), and social impacts (accidents and user time) while maintaining service life and structural safety. The resilience assessment considers the effect of seismic hazard events on structural damage levels and recovery time while maintaining system functionality and structural safety.