ABSTRACT
ABSTRACT Adapting riverine bridges to a changing climate is essential for maintaining the functionality of civil infrastructure. Riverine bridges are vulnerable to damage due to flooding, including damage to the deck, piers, and/or foundation. In order to manage vulnerable bridges, an accurate estimate of future flooding is required. However, this information is not currently available; but rather, a set of flooding scenarios describes the potential climate changes. Probabilities cannot be assigned to the scenarios in the set since the likelihood of climate change scenarios is unknown. This, along with the deep uncertainty in future economic scenarios, complicates the decision making process. When decisions are made, the governing mentality is to maximize expected utility. However, in the face of deep uncertainty, there is also a desire to not choose a suboptimal solution; decision makers do not want to regret having made the wrong decision. This paper discusses the application of Regret, i.e. a metric that corresponds to the feeling of loss and the opportunity lost by having made the wrong decision, in climate change adaptation. Minimizing Regret is presented as an alternative to the traditional objective of maximizing utility (typically quantified through payoff). In order to account for the complexities of decision making under deep uncertainty, the adaptation optimization problem is posed in bi-objective form: maximize payoff and minimize Regret. The proposed framework is applied to an illustrative example for a typical riverine bridge located in the Northwest region of the United States.
