Monitoring And Averting Secondary Collapse Mechanisms In Already Ruined Historic Bridges By Means Of Metric Values Obtained From Archival Photographs And The Geometric Analysis Of The Intrados

This text describes a methodology for the geometric monitoring of abandoned bridges. In order to define the actual state and to monitor the evolution over time it is proposed the use of digital elevation models of the intrados and archival photographs. On the one hand, the digital elevation models might jointly notice the presence of a varied range of conditions in a simple way; therefore, no prior knowledge regarding the active dynamics of the bridge is necessary and, thus, it is a valuable option for preliminary studies, in which only scarce information on this regard is available. On the other hand, the usefulness of stock photographs is analyzed too, in particular, showing the evolution of the case study through the comparison of images taken 50 and 30 years ago.