Methodology for the quantitative risk assessment of road bridges exposed to accidental events

Road bridges in accidental situations represent the most vulnerable components of transportation networks. Accidental situations may be caused by natural or man-made hazards. Decisions concerning protective measures can be based on the probabilistic optimisation of expected costs. In general, total structural costs consist of initial, service costs and consequences of structural failure. The initial cost comprises of construction cost including cost of protective measures; service costs cover maintenance expenditures and safety guards expenses; the failure consequences account for direct costs related to structural failure and follow-up costs due to malfunction of transportation network. Proposed general procedure for the risk assessment is based on Bayesian (causal) networks. It appears that this technique provides valuable background information for the decisions concerning efficient protective measures for bridges endangered by various types of hazards.