Sustainability of Natural Hazard Risk Mitigation: Life Cycle Analysis of Environmental Indicators for Bridge Infrastructure

The performance of structures and infrastructure under natural hazards can have a significant impact on the sustainability of the system, often characterized in terms of environmental, economic, or social indicators of performance. This paper commences with a brief review of the relation of natural hazard performance to sustainability and an assessment of bridge infrastructure sustainability with an emphasis on environmental indicators. A framework for life cycle sustainability analysis (LCS-A) is then posed that elucidates the role of natural hazard risks when evaluating sustainable bridge performance using risk-based indicators of environmental sustainability, including embodied energy and carbon dioxide (CO2) emissions. Its application provides insight on the sustainability of mitigating damage from natural hazards through retrofitting deficient structures, considering uncertainty in the hazard occurrence, structural performance, and repair or reconstruction actions that affect energy expenditure and emissions. A case study is presented to evaluate indicators of environmental sustainability for individual bridges and for a regional portfolio of bridges susceptible to aging and seismic hazards. The results show the significant impact that retrofit can have on reducing the expected value of emissions and embodied energy from lifetime hazard exposure. (C) 2013 American Society of Civil Engineers.