A procedure for bridge visual inspections prioritisation in the context of preliminary risk assessment with limited information

Visual inspections represent the most resource-expensive operation in bridge management systems (BMSs). Consequently, their planning cannot be limited to the results of risk assessments, which are often performed under incomplete or uncertain information, but operating costs should also be accounted for. In this light, this paper presents a new methodology to prioritise visual inspections in BMSs based on risk condition and operating cost assessment. Framed in a context of limited information, the methodology exploits an information gain criterion to tackle potential uncertainties in the risk classification, so enabling to optimize the potential outcomes of the inspection plan. The proposed approach is conceived to be implemented in Geographical Information Systems (GISs) to facilitate the construction of intuitive risk maps and inspection plans. The effectiveness of the framework is demonstrated through its application to a simulated bridge stock whose risk condition was evaluated through the new guidelines for bridge risk classification and management recently adopted in Italy. The presented results highlight the benefits of simultaneously considering bridge risk conditions and inspection costs in defining the inspection plan, hence the usefulness of information theory to prioritise visual inspections. Limitations and future improvements of the proposed prioritisation method have also been highlighted and discussed.