Abstract
The paper examines a thin-walled steel road bridge that has been in service for over fifty years. Due to damage observed during detailed inspections, a comprehensive investigation was necessary to evaluate the structural safety of the superstructure. For this purpose, the new national guidelines for assessing the safety of existing road bridges were used for the first time. These guidelines are based on the new Eurocode prEN 1990-2, which provides the foundation for assessing existing structures. To enable reliable and rational decisions regarding repair or strengthening, a finite element analysis was performed considering the condition survey, NDT, and material testing. The analysis showed that the resistance of some superstructure elements was exceeded by over 600%, and about 180 elements are inadequately safe to carry the actual minimum traffic loads according to the safety standards mandated by the new national guidelines. A comparison between the analysis results and the condition survey identified the same elements where local plastic deformations were observed. Based on the experimental and numerical results within this new assessment framework, the final decision was made to close the bridge for service and replace the existing steel structure.