University of Pisa
Department of Energy, Systems, Territory and Construction Engineering
PhD Dissertation
Italian grain silos
Analysis, conservation and adaptive reuse
of a modern industrial heritage
Stefania Landi
July 2017
Abstract
The present PhD Dissertation focuses on the grain silos built in Italy during the 1930s, when the so-called ammassi
granari collettivi (collective grain storages) were put into service under the pressure of the autarchic Fascist policies.
Those buildings represents today a significant architectural heritage which is largely unused and rarely object of attention.
Since decades, indeed, many national and international institutions have been showing high interest towards the unused industrial heritage, promoting remarkable studies and developing many preservation initiatives. However, in Italy, the attention was focused mainly on other typologies of buildings, or on circumscribed geographical areas. A very limited number of the grain silos built in Italy during that period were deemed as worthy of attention (the silos of Rome, Arezzo, Cagliari and Pieve di Cento), and no one has ever addressed this particular typology of structures considering them as a whole. The only exception is represented by recent studies in economic history, addressing the Fascist policies in the agricultural sector, describing the reason behind the construction of the grain silos, and their strategic role even after the II World War. Since these storage facilities were built by local agricultural companies and consortia, indeed, they were always located in highly strategic positions along the main infrastructural networks and railway lines, in order to optimize both the collection of grain as well as its distribution, and thus they become the knots of a network that was carefully planned.
Nowadays, unfortunately, the awareness of the existence of such facilities and of their interrelation is almost completely lost. Therefore – starting from the assessment of their historical, technological, formal, social and iconic values – the aim of this research is to bring the attention on the whole set of Italian grain silos built during the 1930s as a significant part of the Italian architectural heritage: they, indeed, bear witness of a significant part of the national agricultural and political history, they are expression of the technological evolution which took place in the first decades of the 20th Century, and they were also influenced by the architectural culture of the time and, in particular,
by the Rationalist language.
Thus, the two main objectives of the present research are:
1. to perform a critical analysis of the Italian grain silos of the Fascist period, defining their features, assessing
their values, performing their mapping and initiating their inventory;
2. to propose a framework for guidelines for the conservation and adaptive reuse of such structures, addressing
the main challenges raised by their typology, their construction elements, and their deeply different territorial contexts.
Since many different inputs and points of view were deemed indispensable to address these objectives, the research was developed with a multidisciplinary approach and was carried out through the following phases.
PART 1.
MODERN ARCHITECTURE AND INDUSTRIAL HERITAGE: BETWEEN KNOWLEDGE,
CONSERVATION AND ADAPTIVE REUSE
The first part includes a literature review about many crucial topics: the Modern Movement and its innovative nature, the international diffusion and its complex relationship with totalitarianisms; the development of reinforced concrete since its origin to the worldwide diffusion; the theoretical issues raised by the preservation of modern architecture, related to its temporary nature and standardized components.
In consideration of the specific challenges raised by the Italian grain silos, moreover, this first part makes the point about the practical experiences in the field of modern heritage preservation, historic concrete conservation, steel-and-glass glazing systems conservation, and adaptive reuse of industrial heritage, with a particular focus on grain silos and mills. Therefore, very diverse materials are gathered and synthetized together – from theoretical considerations to practical issues, ranging from a macro dimension (urban, social and economic challenges in adaptive reuse) to the micro dimension (diagnostic and repair techniques for historic concrete and steel-and-glass glazing systems) – with the aim to provide a solid basis to assess the values and significance of the Italian grain silos, and to comprehend the more suitable methodologies for their conservation and adaptive reuse.
The main challenges related to the material conservation of the two main components of the grain silos – reinforced concrete and glazing systems – were found to be linked to the invasiveness of investigation and diagnostic techniques, and to the unsuitability of the available methods and materials for repair, often driven mainly by the concrete industry rather than by conservation principles. As for the challenges related to adaptive reuse, instead, the first issues to be noted was the difficulty in identifying design solutions able to guarantee at the same time functionality, structural safety and formal compatibility, and – most of all – the difficulty in identifying new compatible uses: a decision-making problem, made particularly complex by the many conflicting stakeholders, by the need to reach an economic and social sustainability, and by the deep differences among the territorial contexts where the silos are located nowadays.
PART 2.
THE ITALIAN GRAIN SILOS OF THE FASCIST PERIOD: FROM THE HISTORY OF THE TYPOLOGY TO
THE STATEMENT OF SIGNIFICANCE
The second part includes the in-depth analysis of the Italian network of grain silos, starting from the preliminary reconstruction of the history of grain storage methods, which was deemed necessary to the comprehension of the silos typology itself. The turning point of this history is commonly recognized in the introduction of the “grain elevators” in North America around the mid-18th Century. In these mighty facilities, a bucket conveyor, a steam
engine and a rope-and-pulley power train were put together creating that particular mechanical ensemble – namely, the elevator – that was able to raise the grain directly from the holds of ships to the top of the bins. In the following decades, different techniques were experimented to build the bins of grain elevators, with the aim to limit their structural instability and the risk of fire, and to improve the thermal insulation to allow a better preservation of the product. In Europe, in the early 20th Century, this typology – here mainly called “grain silos” – began to be built in the
major ports, as well as along the new railway lines. A crucial role in the diffusion of concrete grain silos was played by the Hennebique Company, whose patents were widely applied in Italy.
After, the historical national context is analysed, focusing on the agricultural policies of Fascism and the national laws enhancing the construction of silos for the collective storage of grain. Then, the grain silos are described, focusing on their architectural, typological and technological features, as well as on their mechanical equipment and components. Among the Italian grain silos, it was possible to identify three main typologies (silos with vertical cells, with floors, and with hoppers) and to understand their design and construction process: the Italian silos were built on the basis of standardized projects defined by the companies that provided the machineries, an engineer was always called to develop these project in detail according to the specific need of the client (agricultural consortia and companies), while an architect was often called to design the envelope, especially in the major storage centers. This resulted in a number of valuable industrial buildings, characterized by the most functional and innovative solutions, and influenced by the contemporary architectural language.
Then, the rules behind the construction of the network are highlighted: the grain silos indeed were placed in key positions within the agricultural production areas, and in relation to railway lines and major roads. The availability of considerable financial resources allowed the construction of hundreds and hundreds of buildings.
The mapping of the Italian grain silos, performed for the first time as part of this research, has been possible by combining information from coeval manuals and technical magazines, archival documents and even historical postcards. It is advisable however, that the mapping may have further development in the future, because the fragmentation and weakness of historical documentation lead to identify only a portion of the entire network.
Part 1 and Part 2, therefore, consisted in a preliminary gathering and critical analysis and of all data deemed to be relevant to understand the significance of this heritage and to the development of conservation and adaptive reuse policies.
PART 3.
CONSERVATION AND REUSE CHALLENGES IN TWO EMBLEMATIC CASE STUDIES: THE SILOS OF
AREZZO AND ALBINIA
The challenge related to conservation and adaptive reuse is deepened facing two Tuscan case studies – the grain silos in Arezzo (AR) and Albinia (GR). Firstly, a critical analysis of the two contexts is performed, as well as the analysis of the two silos from the typological, formal and structural points of views. After, the silos’ current conditions are assessed through the analysis of types and extension of deterioration phenomena. Then, two (not alternative, but rather complementary) methodologies are applied: (1) the Multi Criteria Decision-Making Analysis method, that was applied to the case of Arezzo, with the aim to identify the best adaptive reuse hypothesis among a number of options (2) a rigorous territorial analysis of the Grosseto Province, that was developed for the case of Albinia, with the aim to define adaptive reuse hypothesis coherent with the needs and identity of the silo’s context.
Then, both the design proposals and master plan defined respectively for the silos of Arezzo and Albinia, are discussed in terms of architectural-formal compatibility, and validated respectively in terms of structural safety and economic viability, since these two aspect appeared as the biggest challenge in the perspective of the silos’ owners and potential investors.
PART 4.
DEVELOPING REUSE AND CONSERVATION POLICIES: A PROPOSAL OF INVENTORY FICHES AND
A FRAMEWORK FOR GUIDELINES
The following step was the definition of a detailed fiche and a synthetic fiche aimed to implement a national inventory of the Italian grain silos, which is expected to enable the Regional governments to define a list of priorities of intervention. The fiches allow to identify the building, to provide a description, to record data about forms and level of deterioration, and to indicate the existing documentation.
Several national and international inventory systems were taken as a reference: the fiche defined by the ICCD Istituto Centrale per il Catalogo e la Documentazione (Central Institute for Cataloguing and Documentation) under the MiBACT Ministero dei beni e delle attività culturali e del turismo (Ministry of Cultural Heritage, Activities and Tourism); the fiche of the “DOCOMOMO Register”, a fundamental reference for cataloguing the Modern architectural heritage; the Arches Heritage Inventory and Management System, developed by the Getty Conservation Institute and the World Monuments Fund; and finally fiche defined by Silosygraneros.es for the inventory of the Spanish grain silos. Specific guidelines for compiling the fiche were defined and different glossaries were developed to help the identification of degradation phenomena.
The last part of this research aims to propose a framework for guidelines for the conservation and adaptive reuse of the Italian grain silos of the Fascist period. Since most of the silos are not protected by law, their conservation and development may not be guided by the principles and criteria usually employed for the designated architectural heritage. For this reason, the primary purpose of this framework is to establish general policies and strategies which may provide a basis for discussing and preparing conservation plans and adaptive reuse proposals for each specific case. The defined policies rang from the macro-dimension to the micro-dimension – addressing the identification of new uses, the control of change, structural safety issues, material conservation – and recalling some fundamental issues, as the need to find a balance between conservation and standard requirements, the attention to the setting, and the need for a proper site management.
The overall objective of this research, therefore, is to provide new knowledge about the Italian grain silos, and to enhance conservation and reuse solutions able to meet the needs of their context while preserving their identity and values.
