Optimisation of maintenance strategy of deteriorating bridges considering sustainability criteria

Facing the contradiction between increasing maintenance demand and limited financial, as well as smaller social and environmental impacts, the optimisation of bridge maintenance strategies should be carried out. In this paper, the assessment model of four objectives, including the safety performance, economic, social and environmental impacts, in sustainability criteria are proposed. Moreover, a systematic optimisation framework of maintenance strategy of deteriorating bridges considering sustainability criteria and a novel decision-making method are developed, based on fuzzy analytic hierarchy process (FAHP) and a decision-making algorithm based on linear programming techniques for multidimensional analysis of preference (LINMAP). The case analysis results verify the effectiveness and superiority of the previous optimisation framework, and also show that the final optimal strategy obtained by the proposed decision-making algorithm can reflect the will of experts well. Compare with the essential maintenance, the implementation of preventive maintenance is more conducive to realise the sustainable development of the deteriorating bridges. The sensitivity analysis results show that the monetary discount rate has a greater impact on the life cycle maintenance cost, which is mainly controlled by the total social cost, while the direct maintenance cost only accounts for a small part.