CONSOLIDATION AND RESTORATION OF HISTORICAL HERITAGE: THE FLAVIAN AMPHITHEATER IN ROME
The recovery and retrofitting techniques adopted for historical structures and archaeological sites face an apparent dichotomy between conservation of constructions and the safety of users. Literatures show several examples where the current day structural safety of historical constructions, gets defined by the nature of past interventions, the compatibility of materials and elements used in retrofitting. The adopted interventions were, in their time, considered innovative, but over the years their compatibility and reversibility leave the historic constructions structurally vulnerable. For these reasons, a careful understanding of the structural systems is fundamental for the implementation of appropriate retrofitting solutions. Especially for monuments and Archaeological sites the objective to be achieved has to be clear, avoiding destructive investigation tests. In this work the instabilities caused by a consolidation intervention on some travertine columns in a sector of the Flavian Amphitheatre, better known as “Colosseum” in Rome, are critically analysed. The current consolidation operations are compared to the previous one. The restoration activity involves in-depth diagnosis process: the historical analysis of the failures and restorations of that area of the Colosseum, a survey of the crack pattern and an indirect investigation on the travertine of the columns. Subsequently the various data coming from the knowledge phase are elaborated, in order to have a correct interpretation of the causes triggering the failure and guide the choice of the most correct retrofitting techniques.