Risk assessment methodology for bridges based on element condition ratings considering different maintenance strategies

Risk-based performance measures provide effectiveness in decision making by combining the probability of structural failure with the consequences of this event. This paper presents a risk assessment methodology for bridges using bridge element condition ratings considering different maintenance strategies. The risk is quantified in terms of expected losses. A reliability-based approach is implemented to compute the component and system failure probabilities. Unlike the common risk assessment approaches, the methodology accounts for possible different levels of component deterioration at any time instant and their probabilities. The Pontis element condition rating system is used to represent these levels.An approach for comparison of different maintenance strategies for bridge components is presented. The maintenance strategies are represented as the actions that improve the component ratings repetitively in time. The expected loss associated with different maintenance strategies and the expected cost of these maintenance strategies are quantified through the lifetime of bridge structures. The approach is illustrated on a highway bridge.