Angelo Salemi

The 1755 Lisbon Earthquake was a catastrophic event for the Portuguese capital and it was violently perceived even in the western half of the Iberian Peninsula. Traditionally, to this seismic event are recognized several buildings damages in Castile and Leon.
In this paper, we analyse the damages that could have occurred in the centre of the region, starting from the reports issued by local governments explaining the extent of the earthquake perception. The study will focus on the Valladolid Cathedral and its bell tower; the latter fell in 1841 and its collapse has been attributed to the Lisbon Earthquake of 86 years earlier.
However, the analysed documentation (some of it previously unpublished) shows that the tower conditions were poor before the earthquake. The structure underwent repairs since its construction to improve its stability. In the 1740s, some architects as Fray Pedro de la Visitación and Antonio San José Pontones worked and made reports on the tower. In 1755, the Lisbon Earthquake was clearly perceived within the cathedral. After this event, the tower was affected by an important repair action by the academic architect Ventura Rodríguez. The repairs did not improve the problems already encountered before the earthquake, especially regarding damages caused by rainwater infiltrations. For these reasons, the collapse of 1841 cannot be attributed only to the seismic effects of the Lisbon Earthquake.

Throughout history, seismic events have always affected Italy. Traditionally these earthquakes have influenced the habits of people and the ways of rebuilding of historic centres. Already in pre-industrial age, the immediate risk perception after the earthquake has helped to evolve the construction methods through empirical and “ante litteram” seismic improvements. In Eastern Sicily, from the disaster of 1693, professionals and workers were engaged in the reconstruction and/or the safety of the huge architectural heritage. The innovative urban plans of rebuilt cities introduce wide streets and large squares that attest an awareness of the need to protect the public safety. About the individual buildings, we note the empirical tendency to "correct" the technical and structural anomalies that deviate from the rules of good practice. These design interventions are documented in more and more relevant way during the nineteenth century because of subsequent earthquakes. To retrieve the efficiency of building elements through the good traditional practices, operations were often invasive for the buildings but have enabled these to survive until today. These transformations altered the original buildings appearance, recoverable through in-depth investigations. Unfortunately, it often happens that the risk perception fades temporally between an earthquake and the other: this involves a progressive "carelessness" about prevention. The 2016 earthquake in Central Italy shows the topicality of the issue and the need to interpret passed earthquakes as forecasting tools of the future behaviour of the historical buildings. Through a cross-reading of the architectural changes and anti-seismic devices in Eastern Sicily in pre-industrial age and through some significant cases, this paper underlines the progressive awareness gained by local professionals from which we can still to draw useful reflections.

This study proposes a meta-approach to the problem of compatible reuse, applied in Catania to the brotherhoods single hall churches, often underused or disused. After making a cataloguing and expeditious anamnesis, we have analysed a framework of needs that would consider the settlement needs in the urban context. Having inserted the data collection in the system, we performed an assessment of compatibility of reuse that satisfies the historic building protection, the reversibility of possible action, and the requirements of the new undertaken functions.

Le strutture portanti in legno delle coperture delle fabbriche tradizionali rappresentano una preziosa testimonianza di attente ed empiriche " scelte ingegneristiche " delle antiche maestranze locali, capaci di trovare raffinate soluzioni tecnologiche perfezionate nel corso dei secoli. Le apparecchiature tecnico-costruttive dell'areale etneo non fanno eccezione. Se ciò ha prodotto procedimenti " standardizzati " e ricorrenti per le architetture ad aula, come i sistemi a capriate o i più semplici e meno efficaci falsi puntoni su setti murari, le emergenze architettoniche a pianta centrale sono caratterizzate spesso da strutture lignee più complesse che, seppur celate dalle volte sottostanti, meritano la stessa attenzione. Il recupero di questi singolari esemplari risulta dunque fondamentale ma si deve confrontare necessariamente con le problematiche legate alla sicurezza nei territori soggetti a rischio sismico. In questo paper, dopo un'analisi di tali presenze nell'areale etneo, si esamina un caso emblematico che ben rappresenta l'uso dei materiali disponibili nel circondario e le tecniche realizzative messe a punto dalle maestranze locali: la copertura lignea della settecentesca chiesa di Santa Chiara a Catania. Si sottolineano infine gli aspetti principali che hanno contraddistinto l'intervento di recupero.