This paper presents a study of the structural safety of a medieval bridge located in the northwest of Spain. This study was carried out using different analytical methods: (1) the Mechanism Method proposed by Heyman, (2) the Virtual Works Method, (3) the Method developed by Livesley using Linear Programming, and (4) Mery's Graphic Method. The last one was used to check the other three methods. To do this we developed software called ANPAF, which contains these four methods. The geometry of the bridge was acquired by data acquisition techniques using a 3D scanner. Given the difficulty of assessing the basis of its actual geometry, a module that allows direct reading from the technical information provided by Terrestrial Laser Scanning (TLS) and orthophotos was developed. This study has allowed us to compare the results from different methods and to see the scope of each with a view towards their utility in collecting data in the field. At the same time, we validated the methods implemented with existing software.