Home 9 Research projects 9 THE MASONRY BUILDINGS IN THE CITADEL OF ALESSANDRIACoordinators: E. Piccoli, C. Tocci, with R. Caterino and E. Zanet

THE MASONRY BUILDINGS IN THE CITADEL OF ALESSANDRIACoordinators: E. Piccoli, C. Tocci, with R. Caterino and E. Zanet


This research, stemming from a research contract with the Ministero dei Beni e delle Attività Culturali e del Turismo – Segretariato Regionale per il Piemonte (La storia della Cittadella di Alessandria dagli anni ’30 del sec. XVIII fino al XX secolo), deals with the construction history of the military buildings inside the Citadel of Alessandria. While these well-known, listed buildings are part of Italian National heritage, they have never been considered, up to this day, in their complex materiality. Our research cross-references the archival information on the citadel’s early history with the close observation of the structures, in order better understand their planning and construction process, and their physical configuration. We attempt to answer to some of the following research questions: what were the construction techniques and materials employed in the Citadel? Who were the main actors involved in construction and how do they relate to the state-of-the art knowledge of their time? How did the buildings perform in their time, and over time? Were any crises and failures recorded, and if so, did they lead to improvements or modifications? How does the materiality of the buildings relate to the reuse / preservation / conservation issues that arise today?


The choice to focus on the 18th and early 19th c. large-scale buildings inside the Citadel, rather than on the defensive works (bastions, outer works), has allowed us to venture into the somewhat uncharted territory of the buildings’ planning and the detailed choices leading to their construction. The information gathered is meant to aid in the competent examination of structural and planning issues in future interventions, and provides also a guideline for research/reuse / preservation issues in Alessandria, and in similar sites.

We have followed two main lines of investigation:

a) An in-depth archival research, within the Buildings’ and Fortification Agency funds (1730s-1800) in the State Archives in Turin, with secondary investigations in Rome, Paris, and in other Turin archives.
b) On-site inspections leading to an understanding of the site and buildings’ layout and construction characters.

Following this first phase, which led to a massive collection of digitized and transcribed archival documents, and of other kinds of documentary evidence (photographs, drawings…), the group has worked on the examination of a selected number of problems, which we felt were particularly relevant and useful for the citadel’s future conservation.

This part of the research is still ongoing, and we can summarize it in the following points.

  1. Masonry construction

The citadel buildings are a remarkable example of early modern brickwork construction. Structures are entirely made of brick masonry with small but significant variations in unit arrangement and bonding systems. The large scale of these massive buildings introduces significant variations that are worth of specific examination: the role of mortar can no longer be overlooked; the mutual connection between parts (walls, vaults, etc) becomes especially relevant. While these buildings look simple, almost every detail is relevant, given the amount of materials and workmanship involved: therefore, even the understanding of a few basic facts about their constitution requires accurate research and cross-referencing. After establishing a consistent timeline of construction and recovering a few key documents (general and specific instructions for building, drawings, etc) we were able to debunk a few ‘myths’, such as one regarding the piecemeal reuse of materials from the demolition of the city buildings (which proved false, as the reuse of old materials was in itself a carefully planned operation).

  1. Foundation systems

The terrain on which the citadel stands is not suited to heavy buildings: the soil in the area is soft, the water table high, and flooding is frequent: water is still, in Alessandria, a constant menace, and the last devastating flood has taken place less than thirty years ago. For this reason, wooden pile foundations have been used throughout the site since construction started, in the early 1730s. The research has uncovered the procedures and materials used for foundation systems, and has established that due to an early (1750) episode of structural failure in the S. Tommaso barracks, an intense debate developed, leading to the adoption of an improved system in the later 18th c. buildings. Accurate drawings have been produced by our research unit, representing the two foundation systems detailed in the construction specifications. The information and interpretation of this data allows to approach conservation issues in the damaged barracks (where cracks and fissures are still apparent), and will be a guide in further research and analyses of the structures in all buildings.

  1. Bomb-proof vaulting and massive roof structures

The constructions within the citadel built before 1815 were made to be bomb-proof (à l’épreuve). 18th century construction defined different ways to achieve this requirement:
a) The use of buildings that were slightly stronger than ordinary but could be adapted to be ‘bomb resistant’.
b) The planning of massive constructions with very thick walls and vaults that could withstand bombs’ impact in any moment, without being pierced nor losing equilibrium.
Both solutions are used in Alessandria, in one instance combined in the same building (the former military Hospital), with a prevalence of the second method.

Our research has determined the specifications, debates, and evolution in the use of this technique, in connection with the general planning of the buildings, the design of the vaults, the use of hidden iron and wooden ties, and of ventilation tunnels. The major problems that have recently arisen at the Citadel in roof maintenance and waterproofing make this part of our research a necessary step towards a rehabilitation of the citadel’s inner works.

While we have barely opened up certain topics for further analysis, our research has improved existing knowledge and provided new insight in the following areas:

  • the buildings’ construction history, from their origins to their present state;
  • the buildings’ typological characters, and their transformation potential;
  • the definition of guidelines for future surveys, structural analysis and tests on materials, highlighting the urgent need for a detailed geometric survey and selected tests;
  • the valorisation of the Citadel’s architectural heritage, with new narratives and details on construction that may be made available to the general public.


Edoardo Piccoli, associate professor in architectural history, Politecnico di Torino
Contact: edoardo.piccoli@polito.it

Cesare Tocci, associate professor in restoration, Politecnico di Torino
Contact: cesare.tocci@polito.it

Roberto Caterino, art historian, architectural historian (Ph.D.); research assistant, expert in archival sources, responsible for the archival research in Turin / Rome
Contact: roberto_caterino@alice.it

Elena Zanet, architect; research assistant, on-site surveys and historical research; author of graphic elaborations and drawings.
Contact: elena.zanet@polito.it

Temirlan Nurpeissov, Elena Rossi, and Maria Chiara Strafella have contributed to the research with their final dissertations for the Master of Architecture degree, Politecnico di Torino.

Short Bibliography

  1. Piccoli, C. Tocci, R. Caterino, E. Zanet, ‘Building on water and the Modern State. Eighteenth century foundation techniques in the fortifications of Alessandria’, pp. 358-373, in J.W.P. Campbell (Eds), Proceedings of the sixth conference on the Construction History Society CHS, Water, Doors and Buildings. Studies in the History of Construction, Queen’s College, 2019, Cambridge, 2019.
  1. Piccoli, C. Tocci, R. Caterino, E. Zanet, ‘Lo Stato entra in cantiere: sviluppo e utilità di una fonte seriale settecentesca’, pp. 217-224, in A. Marotta (Eds), Proceedings of the international congress Defensive Architecture of the Mediterranean. International Conference on Modern Age Fortification of the Mediterranean Coast, FORTMED 2018, Castello del Valentino, 2018, Torino: Politecnico di Torino, 2018.

Master of Science thesis
Student: Ilaria Martella
Tutors: Cesare Tocci, Edoardo Piccoli
Title: La lettura costruttiva dell’architettura muraria storica. Il quartiere San Carlo nella cittadella di Alessandria – Constructional analysis of historical masonry architecture. The San Carlo barracks in the citadel of Alessandria
Status: defended in 2019
Link: here
Abstract: (from webthesis)

The fortified citadel of Alessandria was born in the XVIII century within a large circuit of fortresses “alla moderna.” The research is centered on the study of the second building born inside the bastion, between 1760 and 1768: the San Carlo barrack. After a brief historical analysis regarding the context in which the factory is inserted and an identification of the typological characteristics that allows to associate the San Carlo to the types of barracks models released in 1700, the thesis aims to investigate the design criteria and the construction techniques used for the construction of the neighborhood through the critical reading of bibliographic and archival sources and direct feedback with the factory. In addition to expanding the knowledge on the history of the citadel of Alessandria and the construction of Savoy Piedmont, the material produced in this research could be the beginning on which to set up a diagnostic study for a project of recovery and functionalisation of the architectural heritage.

Student: Anna Rossi
Tutors: Cesare Tocci, Edoardo Piccoli, Roberto Caterino
Title: La lettura costruttiva dell’architettura storica dalle fonti d’archivio al rilievo diretto. Il quartiere San Tommaso nella Cittadella di Alessandria
Status: defended in 2019
Link: here
Abstract: (from webthesis)

Alessandria’s citadel is a massive presence in the piedmontese territory. It was born from the ruin of Bergoglio district and then it was center of sieges and battles from XVIII and XIX centuries. The study purpose is to deepen the knowledge of the first construction built within the fortress between 1749 and 1760: St. Tommaso’s building. The aim of the thesis is to reach a major architectural and structural comprehension of the subject through the combined analysis of bibliography, metric survey and sources examination. After a brief overview of the barrack typological characters, that allows to link St. Tommaso to distributive and functional models defined by the ancient technical literature, the thesis focus on direct survey of the building with the purpose of define constructive manners and formal characters. Those had been reconstructed through a critical reading of the of the archive materials (instructions, technical specifications and contracts) producted by the Azienda Fabbriche e Fortificazioni, between 1717 and 1797. Azienda which programmed and controlled the construction activity in the whole Kingdom of Sardinia. The analysis of the material coming from the archive of this institution along with on-the-spot surveys leaded to the comprehension of constructional systems but moreover to a narration of the events of the construction site, from the point of view of the different subjects involved. Besides a specific historical interest that increase the knowledge of the Alessandria’s Citadel and of the eighteenth-century piedmontese construction techniques, the thesis is also a propaedeutic tool for a future design because it could direct diagnostic investigations.

Student: Maria Chiara Strafella
Tutors: Cesare Tocci, Edoardo Piccoli, Roberto Caterino, Elena Zanet
Title: Forme costruttive della Cittadella di Alessandria tra lettura diretta e fonti d’archivio
Status: defended in 2018
Link: here

Student: Temirlan Nurpeissov
Tutors: Edoardo Piccoli
Title: The Citadel of Alessandria: tracing the documents of a great military complex
Status: defended in 2017
Link: here

Abstract: (from webthesis)

The following work concentrates on the study of military architecture, and in particular on the citadel of Alessandria. Once built as a strategic defence site for the State of Savoy, the vast military complex is now dismissed and largely unused. On the one hand, the citadel poses a great challenge: the structure was built in the XVIII century with the function that is not a part of the today’s life. On the other hand, the citadel of Alessandria is a unique object that has a great potential to be reused and to become an integral part of the modern life. This research is a part of a bigger study, that is starting to develop, in the collaboration with the state, local institutions and the university (Politecnico and Future Urban Legacy Lab (F.U.L.L)). Furthermore, it demonstrates that the citadel of Alessandria is one of the most mature examples of the fortificazione alla moderna. The study of a series of 18th century contracts signed for the construction of the complex and of the attached drawings follows, and highlights some of the unique material qualities of the cittadella. The second part couples the historical study and the multiple personal inspections, trying to understanding the current state of the military complex. In particular, the spaces of the ex-hospital building, the largest building built within the wall perimeter, are examined.