Grey Fuzzy Comprehensive Evaluation of Bridge Risk during Periods of Operation Based on a Combination Weighting Method

Bridge safety during operating periods is a primary concern worldwide, and the evaluation of bridge risks is a critical aspect of ensuring bridge safety. The most common methods used for bridge risk evaluations include fuzzy comprehensive evaluations, grey system theory, fault tree analysis, the Kent index method, and data envelopment analysis. However, these approaches are highly subjective and have uneven distributions when determining the weights of risk indicators. To improve the accuracy and feasibility of bridge risk evaluations for a given period of operation, we first establish bridge risk indicators and assign subjective weights to each indicator based on an analytic hierarchy process. Additionally, objective weights are assigned to each indicator according to an entropy weighting method. Then, the combined weights of each risk indicator are obtained by applying game theory principles. This enables the construction of a degree of membership matrix comprising these risk indicators, which is established according to an expert grading method and grey fuzzy theory. Finally, the evaluation results vector is calculated, allowing the risk level of a bridge to be assessed according to the principle of the maximum degree of membership. Overall, this study provides a more accurate and objective method for evaluating bridge risk during a given period of operation.