The crucial role of geotechnical engineering in the preservation of historic heritage is already well known and the need for accurate site investigations and long term monitoring data is essential for a proper study of valuable historical monuments. In such a framework, this paper describes the case study of the two leaning towers of Bologna (Italy): Asinelli and Garisenda, also known by locals as Two Towers. Located into the heart of the city, such ancient structures are the most important symbols of the medieval splendor of the town. Garisenda Tower (48.16 m tall from the ground level and 7.4 m wide at the base) was built few years before the Asinelli Tower (97.20 m from the ground level and 14.2 m wide at the base) at the end of 11th century AD. Originally, Garisenda Tower was 60 m high but in 1353 it was partially demolished to 48 meter high, because of its dangerous leaning. The Two Towers in Bologna are sensitive masonry structures. They have always been affected by structural problems, especially Garisenda Tower, whose inclination is still cause for concern for local authorities. Historical background, recent and past geotechnical investigation and monitoring of the site are herein described. The preliminary results of such investigations enable to define the local soil profile, the geometry of the foundations and the relevant ground water conditions. The study is a preliminary step for the development of a detailed and reliable geotechnical model of the soil-foundation system, a crucial element for a reliable prevision of the possible future behavior of the towers.

Le Due Torri di Bologna, localizzate nel centro storico dell’antica città universitaria, sono simboli del medioevale splendore della città. La loro conservazione è una priorità assoluta per l’intera comunità e motivo della recente campagna di indagini condotta tra Maggio e Agosto 2016. Le nuove indagini sono state eseguite per completare lo stato delle conoscenze sulle fondazioni e sui terreni di fondazione delle Due Torri, con lo scopo finale di creare un modello geotecnico affidabile. Questo contributo descrive i risultati preliminari di tale campagna d’indagine (caratterizzata dall’esecuzione di prove in sito, prove di laboratorio e dall’installazione di un nuovo sistema di monitoraggio con piezometri e assestimetri profondi), partendo dagli studi condotti per identificare il contesto storico in cui furono costruite le torri, le modalità costruttive delle fondazioni e le vicende storiche, per poi passare all’identificazione del contesto geologico ed infine alla descrizione dei risultati preliminari delle nuove indagini.

Indagine geotecnica sulle fondazioni delle due torri a Bologna

M. Marchi;I. Bertolini;L. Govoni;L. Tonni;G. Gottardi;A. Mastrangelo
2017

Abstract

The crucial role of geotechnical engineering in the preservation of historic heritage is already well known and the need for accurate site investigations and long term monitoring data is essential for a proper study of valuable historical monuments. In such a framework, this paper describes the case study of the two leaning towers of Bologna (Italy): Asinelli and Garisenda, also known by locals as Two Towers. Located into the heart of the city, such ancient structures are the most important symbols of the medieval splendor of the town. Garisenda Tower (48.16 m tall from the ground level and 7.4 m wide at the base) was built few years before the Asinelli Tower (97.20 m from the ground level and 14.2 m wide at the base) at the end of 11th century AD. Originally, Garisenda Tower was 60 m high but in 1353 it was partially demolished to 48 meter high, because of its dangerous leaning. The Two Towers in Bologna are sensitive masonry structures. They have always been affected by structural problems, especially Garisenda Tower, whose inclination is still cause for concern for local authorities. Historical background, recent and past geotechnical investigation and monitoring of the site are herein described. The preliminary results of such investigations enable to define the local soil profile, the geometry of the foundations and the relevant ground water conditions. The study is a preliminary step for the development of a detailed and reliable geotechnical model of the soil-foundation system, a crucial element for a reliable prevision of the possible future behavior of the towers.
2017
La geotecnica nella conservazione e tutela del patrimonio costruito
649
657
Marchi, M.; Bertolini, I.; Govoni, L.; Tonni, L.; Gottardi, G.; Mastrangelo, A.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/609137
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