The Municipal Hall of Crevalcore. Remarks about history as a tool for restoration project

The paper illustrates the analysis carried out on the Municipal Hall of Crevalcore – a small town near Bologna damaged by the Emilia earthquake of May 2012. Following a methodology al- ready tested in several post-seismic situations, the study takes the constructional and evolutionary history of the building as the core of the knowledge process preliminary to the restoration project. Although such an approach is now also suggested in the Italian Guidelines for Seismic Vulnerability Assessment and Mitigation of Cultural Heritage (Min. IT, 2011), the relationship be- tween the historical research and the building weaknesses and, more importantly, between recognized weaknesses and restoration choices, does not seem to emerge clearly enough in the available literature. With reference to these preliminary remarks, the paper aims to show how the search for the causes of damage can be fruitfully supported by an historical analysis of the building, and how the acquired knowledge is crucial for the definition of minimal interventions, both conservational and effective from the point of view of safety. Analysis of the Municipal Hall of Crevalcore and, indeed, the whole historical centre, started in the first post-seismic phase, and the aim was to document and interpret the damage caused by the earthquake. The results of the preliminary expeditious survey show that the greatest damage was concentrated on the buildings which include porticos at street level (Carocci et al., 2013). In this way, a well-defined area made up of the two main streets in the centre was identified. The decision to carry out an in-depth analysis of the seismic behaviour of the Municipal Hall was motivated by its civic and institutional importance: it houses various public functions and is used by the public sector including the Municipal Police, commercial activities, and local associations on the ground floor, and local government offices and boardrooms on the upper floors. The damage present in the Municipal Hall is also representative of that identified more generally. The study was carried out following a methodology which the authors have often used in re- cent years in the analysis of buildings which were heavily damaged by the earthquake (Carocci, 2013). In this methodology the 'critical reading' of the building's configuration has a central role. It involves two areas of analysis: on the one hand, the survey of the building and, on the other, the historical research. These are both aimed at highlighting the historical and recent transformations which may have influenced the building's behaviour during the earthquake. In the case of the Municipal Hall of Crevalcore, the historical research produces a telling picture of the consequences of the constructional history on the identification of a building's weaknesses in the event of an earthquake.