The activities of the International Committee for the Safeguard of the Leaning Tower of Pisa and the interventions carried out on the Tower are reported in this set of volumes, wich are published as “Volume Speciale” of the Bollettino d’Arte.

A subcommittee, supported by the Ministry of Cultural Heritage, the Scuola Normale Superiore and the Opera della Primaziale Pisana, chaired by Salvatore Settis, consisting of Michele D'Elia, Michele Jamiolkowski, Giorgio Macchi, Fernando Veniale and Carlo Viggiani, was entrusted with their preparation. An editorial board, consisting of Gisella Capponi, Lucia Franchi, Simone Ghelfi, Stefania Lodola and Nunziante Squeglia, drafted the texts and prepared the figures under the guidance of Mariacristina Pepe. The names of the editors of each chapter are indicated, but the International Committee as a whole should be considered the collective author of the work.

The Bollettino d’Arte board, consisting of Antonietta Fermo, Loredana Francescone, Donato Lunetti, Luisa Tursi, Elisabetta Diana Valente, was entrusted with the final editing.

These Proceedings are published in three volumes, that are accompanied by a portfolio of drawings. They present a summary of the impressive range of activities undertaken by the Committee, in a spirit of intense interdisciplinary collaboration. Thanks to these studies and investigations, innovative technical solutions were developed to solve the age-old problem of the preservation of the monument.

 

Volume I is an introductory volume that provides a general description of the monument and a concise, but thorough, account of the studies and researches on the geotechnical and structural problems and the restoration of the Tower surfaces. The volume is intended as a general picture of the actions that were carried out by the Committee to accomplish its task. After presenting the historical and archaeological survey of the subsoil of the “Piazza”, it offers a general description of the Tower geometry and depicts the history of its construction, which was obtained from the archives and from a bibliographic research promoted by the Committee. An interpretation of the behaviour of the monument is also attempted. The restoration works carried out over the centuries, the solutions proposed prior to 1990 to stabilise the monument, the preliminary studies carried out by the Committee in order to establish the most effective means of stabilization and structural reinforcement and to define a plan of restoration, the temporary and definitive solutions that have been implemented to improve the structural and geotechnical stability of the Tower are all reported and discussed.

A final chapter is dedicated to the presentation of some examples of the use, in the past, of underexcavation to stabilise tall buildings.

Though remaining rigorous in its approach, the text is highly readable, having been conceived for non-specialists interested in the actions that have been undertaken.

 

Volumes II and III, on the other hand, are intended for those who are interested in more detailed knowledge of the geotechnical and structural problems and of the questions related to the restoration of the Tower surfaces.

The second volume deals with the geotechnics of the Tower. It gives a summary of the data that had been collected since the early 1900’s concerning the subsoil profile and the physical, mineralogical and mechanical characteristics of the soils, and presents the methods and the instruments adopted for the monitoring of the movements of the Tower and its foundations. A summary follows of the statistical interpretations of the historical measurements and of the theoretical studies and physical and numerical modelling aimed at elucidating the behaviour of the monument. Finally, the temporary and definitive measures for the geotechnical stabilization are presented, while the operational processes and the technologies developed to stop the progressive, inexorable tilt of the Tower are reported in some detail.

Volume III deals with the structural reinforcement of the Tower and the restoration of its surfaces. It is subdivided into two sections. The different investigations, aimed at a diagnosis of the state of the masonry and the studies concerning the structure, are reported in the first section. The interventions that were carried out to strengthen the masonry of the Tower are also presented; these interventions led to a substantial improvement of the structural safety. The studies concerning the restoration of the surfaces, the experimental investigations and the tests for the definition of the methodologies for the material restoration are presented in the second section.

The texts are in Italian, but there are extensive English summaries and bilingual captions for the many figures, the black and white and the colour photographs.

The drawings in the enclosed portfolio report the geometry of the Tower, as determined in the new architectural survey of the monument and the “Piazza”. Some samples of the maps of the state of conservation of the masonry are also reported.

All the figures and photographs, if not otherwise indicated, are the property of the Opera della Primaziale Pisana and of the International Committee; the owners of the other figures are indicated at the end of each chapter.

References are given at the end of each volume. These list only the sources quoted within the text, and are not intended as a complete and comprehensive record of the impressive amount of studies that have been carried out concerning the Tower. The technical documents (research and design reports, drawings, etc.) prepared for the Committee are also listed in the references. These are named “Affidamenti”, as they result from a task entrusted by the Committee. A complete list of the technical documents is provided in Volume I. “Affidamento”  2 consists of a large and detailed catalogue of references on the Leaning Tower.