Le pietre da costruzione del Piemonte

Quando un ambiente naturale è destinato ad essere coltivato la sua presa di possesso conduce a ridisegnare il territorio; si sviluppa così un'architettura che nasce dalla terra, con materiali da questa direttamente provenienti e determinata da stretti reticoli di confini che materializzano il suo controllo legale. Opere di irrigazione, confini dei lotti, strade di comunicazione sono tutti elementi che concorrono a costruire e a tracciare il paesaggio secondo strumenti e regole urbane a cui si interfacciano volumi di differenti dimensioni e forme. L'uomo diviene così artefice dell'edificazione dell'ambiente naturale: recinge lo spazio coltivato, realizza la sua abitazione, coltiva i campi. Ma nel gesto dell'edificare si nasconde anche un significato semiotico -come afferma Emilio Turri -ossia il segno del possesso, la legittimazione di una occupazione e quindi la percezione chiara di una presenza all'interno del paesaggio 1 . Così per coltivare un territorio l'uomo finisce per costruirlo, assegnandogli una connotazione che diventa immagine della propria attività, dell'organizzazione, del lavoro e della propria cultura. Anche Carlo Cattaneo, osservando il paesaggio, afferma che «un popolo deve edificare i suoi campi come le sue città» 2 e per primo ha sostenuto il concetto di «paesaggio edificato» 3 . Ai tracciati naturali dei fiumi e dei torrenti si interfacciano quelli artificiali delle strade e dei muri di confine, mentre tra le ombre della vegetazione arborea si stagliano volumi fatti di pietra che il tempo trasforma in relazione all'uso e alle necessità dell'uomo. Ecco che la presa di possesso da parte di una comunità individua tutte quelle risorse necessarie per la sopravvivenza e induce a ridisegnare il territorio assumendo una connotazione antropica.

2018

La Pietra di Visone viene estratta dall'età Romana e utilizzata nel corso dei secoli come pietra da taglio e per la produzione di calce. La relativa Formazione geologica consiste in un circoscritto affioramento di depositi di biocalcarenite datati al Miocene, localizzabile nel Bacino Terziario Piemontese, tra Visone ed Acqui Terme. Il presente contributo ha come obiettivo la pubblicazione di una sintesi dei risultati di ricerche pregresse (Allemani 2013), mirate alla mappatura delle cave storiche, alla determinazione dell'areale di diffusione della pietra in opera e a un primo catalogo dei monumenti in cui è stata individuata. Si prefigge inoltre di meglio definire i limiti cronologici del suo utilizzo, ampliando le riflessioni in merito alla contrazione delle attività estrattive durante il Medioevo e alle conseguenti soluzioni architettoniche adottate. Dalle precedenti indagini emerge un uso discontinuo della Pietra di Visone, nelle due varietà bianca e grigia, fino al Novecento, con interruzioni in epoca medievale, in cui si individua un caso emblematico di reimpiego di materiale romano, relativo alla Cripta del Duomo di Acqui Terme (XI sec.). Testimonianza più significativa rilevata in riferimento al periodo, questo sito può essere considerato un rappresentativo specchio dell'economia del tempo. A partire dal XV sec. si registra una considerevole ripresa del suo impiego, con particolare frequenza in apparati decorativi di palazzi signorili e chiese, che troverà apice nel secolo successivo in complessi monumentali come Santa Croce di Bosco Marengo. E' ricorrente l'uso della colonna a fusto monolitico, utilizzata in portici e loggiati, elementi caratterizzanti l'architettura aulica locale. Si ritiene importante evidenziare che nell'ambito del Basso Piemonte, la Pietra di Visone abbia indirizzato un gusto stilistico che non si ritrova in nessun'altra zona oltre l'Acquese. La Pietra di Visone è oggi oggetto di valorizzazione dell'Ecomuseo della Pietra e della Calce, inserito nella Rete degli Ecomusei della Regione Piemonte.

Analisi su alcuni edifici di culto dell'area astigiana e alessandrina della prima metà XI secolo

The growing interest in the "Modern Architecture restoration raises new methodological and operational questions about a lot of building techniques extraneous to the historic tradition and new materials derived by industrial innovation in the early XXth century. Cement and derived products have an essential role in the modern architecture language; in particular the production of surfaces and artefacts realized by false stone (also know as artificial stone or litos-cement). The spread of artificial stones began at the end of the XIXth century, when the application of “stucco” and “marmorino” was replaced by cement that, properly pigmented, appears like a natural stone. The enhanced "eternity" of the cement has been proven untrue, and many façade or elements realized with artificial stone elements have already shown signs of advanced degradation and they need appropriate interventions. Cultural and technical recovery is essential today for the conservation of these artefacts, through a necessary knowledge of these techniques, forming and installation work. The artificial stone artefacts are the result of a fine technological process, but also the product of a craft. This duality requires a careful consideration during the project for the intervention, not only restoration one but also a simple maintenance. Key-words: cement, artificial stone, false stone, fascist autarchy, conservation

2000

Projects on the stone Studies on the subject, considering the scale archaeological embedded in the theme, revealed as the focus of the layouts found by archaeologists on artefacts during excavations, abundantly documented in specific texts , focused primarily on " traces of processing "and" guidelines or of faith, "especially in Greek and Roman times, providing a thorough sampling of what is now unanimously recognized as a standard practice of the construction process. Through extensive bibliography can find a classification summarized as follows: - Traces of machining tools such as chisels, chisel, pencil lead-colored; - Traces on the surfaces of discharge and on the faces of contact, such as anathyrosis, (special processing of the contact faces, which presents itself as a band and finished contornante adjust one or more margins of an element, with the central part which remains retracted ); - Traces of guidelines for the installation of construction elements: stone blocks and drums of columns, or for installation of decorative elements, such as triglyphs, metopes, geison; - Tracks for the connection of these elements: holes of the lever, casting, receipts for polos and empolion (particular connection system consists of an element fitted with a pin and another equipped with built-in); - Traces to assemble and identification: brands of masons, contractors, initials, letters and symbols. The ultimate goal of this classification lies in the attempt to trace a clear date of the article studied through the identification of repetitive elements, certain well-recognized and then chronologically. The arguments just given, supported by a detailed bibliography, now formed a body of work very good and well established, thanks to the efforts by archaeologists in a field of almost absolute dominance. Unlike the traces of drawings engraved in stone elements on site, construction parts and decorative, whose interpretation is not yet unanimous, is a field under development, which meet in a sort of doctrine to its strong multidisciplinary archaeological experiences and architectural expertise. For some scholars they represent real projects of architectural details, the true scale, for others, would be objective representations of the parts made, for others still graphical models, scale, used to control the phases of implementation . From what has been said and the introduction of what would later be discussed more thoroughly, it is noted that in some historical periods and in some geographical areas the use of the tracks had become common practice in the conduct of a construction site, is identified in the case of engravings numerous archaeological sites in Greece, archaic, Hellenistic, Roman monuments in the main, especially in the Imperial age, and major French Romanesque and Gothic cathedrals. To confirm this, and how most obvious example is enough to mention the numerous recordings tracked at the main architectural works of the Roman Empire, built or restored during the first and second century. A.D. under the reign of the Flavian and Antonine dynasties in Italian cities such as showing the path of an arch with concrete amphitheater SMCapua Vetere, the two gables with capital on the pavement entrance of the Mausoleum of Augustus Rome, executed for the portico of the Pantheon, the incisions for the realization of the grooves of the Temple of Hadrian and Pantheon, the capital of the Baths of Agrippa Laconicon have been reported on the Schedule which the main lines for sizing, the guidelines carved on the entablature of the Temple of Vespasian at Rome, and the same in Brescia, or the tracings in certain cities of the provinces as a foreign Sabratha in Libya, Baalbek and Jerash Lebanon. The proposed classification follows two major addresses, the first identified as "Paths Project", with a sense of architecture, which has the main topics "Paths to work site", ie those paths, large substance, found in the circumstances or, some cases, on the same articles, the "Paths of detail on architectural elements", ie those of lesser magnitude, identified on the details for their realization, and finally the "Nomograms", those paths, ie, comparable to geometric diagrams or otherwise signs are part of graphics operations used to trace, set the measurements of a known element, in other, unknown factors. In "Paths to work site" are, in some cases, also including tracks, which by their nature should be categorized as "assembly", but given their size and nature of "meta" is more suited to this second class is the case of some extended compound paths simultaneously guidelines, level lines and axes of symmetry, those, namely, that Ruiz de La Rosa calls "de Dibujos replanteo" identifying the procedure used more than once he saw the "replanting "principal elements constituting an architectural work, the sketch of the designer, often out of scale, directly on the strong, a true to scale. This procedure allowed to check the validity of the alignments of the axes and then make any changes. The second, identified as "Paths of assembly", with archaeological sense, has, however, as the field of implementing the "Guidelines" that is, those incisions performed "in situ" by the juxtaposition of structural elements and control the placement of architectural elements as columns, walls and perimeter marked, and detail elements as metopes, triglyphs, capitals, etc.., and the "marks" that all that body of signs, symbols, letters and numbers that were used by the count of working hours of workers, identification of the blocks in the quarries, the previous numbering assembly of architectural structures composed of multiple elements, simple signs superstitious. The handling of that issue, the apparent strangeness of the tracks with the theme, assumes an important affinity with it, if interpreted as a complement to the design procedure. The trademarks, in fact, in all its different types, they fit perfectly in design methodology defined by the engravings and the paths of the yard, providing a series of explanations and clarifications otherwise not feasible, like annotation metrics, morphological and technical Nowadays we use in preparing the graphics design. Through this reading, which significantly reduces the time lag with modern methods, it will clear the construction process of an artifact in the ancient world, starting from its concept phase, to the preparative, to that, finally, embodiment. The classification as defined, also can not ignore the historical-chronological approach, with the aim of controlling the development over the following centuries, so that any tramandazioni, as well as periods when the use of these procedures was very healthy and consistent. I think, ultimately, be stated that the work is not aimed solely at identifying these construction procedures, it has even less claim to catalog all existing examples, but wants to be, above all, the attempt to identify, through a "process "historical-chronological, a baseline for future studies on the origin of the architectural design today is understood as the Executive.

Recensione della I conferenza del 3 Novembre 2014 all'interno del ciclo "Il racconto delle pietre" per ricordare i 950 anni dalla posa della prima pietra della Cattedrale di Pisa.

Studi Piemontesi, 2019

(a cura di) Livio Tonso 611 Perché si dice Turin e non Torin? Armonie vocaliche e simili fenomeni del piemontese Ritratti e ricordi Giovanni Tesio 619 Nuto Revelli, uno scrittore "a parte" Marco Debenedetti 631 Per il decennale di Nico Orengo Andreina Griseri 635 Specchio emblematico e memoria illuminata. Dedicato a Sergio Mamino Documenti e inediti Giosuè Pier Carlo Bronzino 641 Un santuario mariano nella pianura vercellese. Dalle fonti d'archivio all'interpretazione del cantiere storico della Beata Vergine del Trompone in Moncrivello Simonetta Tombaccini 659 Una stagione a Torino nel 1819, dall'epistolario della contessa Flore de L'Escarène

Arheoloski Vestnik, 2020