Low environmental impact consolidation works in the rock cliff of Civita di Bagnoregio (Central Italy)

Abstract

The work illustrates the design solutions prepared and implemented to mitigate dangers and geomorphological risks in the cliff of Civita di Bagnoregio (Central Italy). Civita is located on a tuff cliff for centuries subject to landslide phenomena that have resulted in the progressive retreat of the slopes and today jeopardize the very existence of the town, so much so that Civita is widely known as the "dying town". In recent decades, Civita has been affected by new and serious occurrences of landslides, focusing the attention of the town's administrators and the wider scientific community on the problem of safeguarding the town's existence, both with respect to civil defense and the conservation of its environmental and architectural heritage. The proposed solutions are the result of more than 20 years of analyses, elaborations and theoretical modeling, and represent one of the most innovative models toward the consolidation and securing of historical towns at risk of landslides. The work proposes to take advantage of the lessons learned in the past toward securing Civita di Bagnoregio, and highlights the need to mitigate such effects on the cultural heritage through interventions that are capable of effectively containing the movement of the cliff, while being at the same time sustainable and of low impact. The paper illustrates the fundamental tenets behind the methodologies and procedures for sustainable intervention and for the identification, on the basis of a careful and rigorous understanding of the ongoing natural phenomena, of appropriate techniques and technical choices for the implementation of works that have a minimal impact on the existing cultural landscape. This paper analyses thoroughly the approach and investigations that have led to the structural reinforcemets of the north side of the tuff cliff of Civita from reinforced concrete shaft excavated in the tuff. These works have had no visual or material impact on the valley or the slopes of Civita, and have made it possible for the first time to carry out an innovative consolidation program, a welcome departure from more traditional and less effective methodologies. © Springer-Verlag Berlin Heidelberg 2013.