This paper presents how a Failure Mode and Effect Analysis (FMEA) with fuzzy logic-based aggregation of the assessments criteria provides decision maker with key figures concerning the risks emerging from aging civil engineering structures. The determination, adaptation and calibration of both the FMEA and the assessment criteria draw on a variety of already available information sources. Inspection data repositories and the maintenance management system help to set-up the relevant cause-and-effect chains and the respective failure modes. The risk factors are adapted to the specific influences regarding civil engineering structures and calibrated based on available data and expert knowledge. The aggregation of the risk factors applies Fuzzy Logic to obtain relevant key figures, like risk priority numbers or risk profiles. Using the example of the prioritization of maintenance measures for weir gates on a river in Germany illustrates the benefits of the developed key figures.