Conservation/Reconstruction. Small historic centres. Conservation in the midst of change.

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Rodica Crisan

Donatella Fiorani

Loughlin Kealy

Stefano Francesco Musso

E d i t o r s

SMALL HISTORIC CENTRES

CONSERVATION IN THE MIDST OF CHANGE

CONSERVATION

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Editors

Rodica Crisan, Donatella Fiorani, Loughlin Kealy, Stefano F. Musso Copy-editor and proof readers

Marta Acierno (French texts) Anna Kealy (English texts) Graphic layout

Emanuele Gabellini · Quasar

Published by EAAE · Hasselt, Belgium · 2015 Printed in It aﬁche CDC srl ISBN 978-2-930301-63-1

No part of this book may be reproduced in any form, by print, photoprint, microﬁlm or by any other means en permission from the publisher.

EAAE

European Associa or Architectural Educa

ENHSA

European Network of Heads of Schools of Architecture

EAAE Tr chitectural educa

This project has been funded with the support of the European Commission. This publica reﬂects only the authors’ view, and the Commission cannot be held responsible for any use which may be made of the informa on contained therein.

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Università degli Studi di Genov to di Scienze per l’Archite a Hos a” Università di Roma. Facoltà di Archite a

to di Storia, Disegno e Restauro dell’Archite a

This book presents the papers en by 62 ts following the 4th Workshop, organised by the Conserva Network of the European Associa for Architectural Educa and European Net-work of Heads of Schools of Architecture in 2013 in Italy.

The workshop was a ended by 70 ts represen Belgium, Canada, France, Germany, Greece, Hungary, Ireland, Italy, Montenegro, Portugal, Romania, Slovenia, Spain, Turkey, United States of America, United Kingdom.

Scien ee

Rodica Crisan Donatella Fiorani Loughlin Kealy

Stefano Francesco Musso Support to the organisa

Marta Acierno, Silvia Cutarelli, Adalgisa Donatelli, Francesca Geminiani, Barbara Malandra

with con om

Ganesh Poggi Madarena, Giovanni Tamburro, Fabiana Ra aola Sannicandro, Serena Zulli Illustra o the text were provided by the authors, organizers and editors.

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THE Cons Erv aTion of THE sma l l Er HisTori Cal CEn TErs

bETw EEn u sE a n d s Eismi C sa f ETy

M. Teresa Campisi

Università degli Studi di Enna “Kore”, Italy teresa.campisi@unikore.it

The conserva of small historical centres the territory cannot be thought of separately from issues of use and safety.

Safeguarding authen and working within compa func choices, prior-conserva could require excep to the transforma need, and therefore a decrease of the ‘use value’. From another per e, due to requirements for main-tenance arising from the carrying out of its ‘use value’ can become a guarantee of maintenance of the ﬁxed asset over notwithstanding a decrease in its original authen .1_{Thus, the technical interven} _{in buildings are not independent, since the}

safety level is inﬂuenced b

These observa however, are linked to the ev of current conserva de-bates, since in the past a direct and unequivocal rela between damage and urban

recons xist.

During the recons period a er the 1693 earthquake of the Val di Noto in Sicily, decisions en depended on the property status of when the level of damage was extremely high.

The city-states were dependent on the Spanish monarchy, so on-site recons was en preferred because of their strategic defense (such as the case of Syr-acuse or Augusta). As for the feudal towns, various procedures were used depending on their smaller or greater isola from main commercial routes. This was especially the case with mountain or hill towns, which were relocated to ﬂat plains (such as Noto and Avola) with a be er c to communica routes. Some hill towns instead were expanded or rebuilt in the valleys because of the social dynamics of the various

residen-groups (Ragusa), or else their urban design underwent modernisa on the same site (Catania).2_{The post-seismic recons} _{en became an opportunity for}

improve-ment of formerly adverse socio-economic c well as a chance to create be er safety standards for the epoch (Fig. 1).

Earthquake safety issues took on a high priority in recons under the Bourbons, a er the 1783 Calabrian-Sicilian earthquake, thus crea an urban se ts and earthquake-proof buildings. Urban planning and ‘earthquake urban planning’ tended to be iden

Similarly, in 1908 a er another earthquake in this area, the recons techniques did not follow the 1783 model. Instead ‘earthquake urban planning’ overlapped the pre-exis urban se t, while building recons became an opportunity for tes w an ons einforced concrete3_{(Fig. 4).}

Later devasta g seismic events in Italy (Belice Valley, 1968; Friuli, 1976; Irpinia, 1980) witnessed the use of reinforced concrete for strengthening or rebuilding, bringing about a remarkable loss of historical authen .

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FIG. 1. The recons of the city of Ragusa (Sicily, Val di Noto). On the right, the old centre on an elevated site; on the le w town with a regular, an yout on a ﬂat area.

FIG. 2. The Baraccata House. An an type with a structure used for recons er the 1783 Calabrian-Sicilian earthquake. From: Vivenzio, G., 1784. Istoria de’ tre in generale ed in o-lare di quelli della Calabria e di Messina. Naples.

FIG. 4. The an adjustment of the urban layout of the pre-exis city of Reggio Calabria a er the 1908 earthquake. From: Bara a, M., 1909. La catastrofe sisimica calabro-messinese (28 December 1908). Florence.

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As regards the decisions made for urban planning, the heritage of the Belice and Cam-pania territories were subjected to an extensive process of urban memory dele This was the result of transferring the towns to other loca and of new cons on the previous sites. By way of contrast, in Friuli the strong feelings of a achment to the original sites prevailed, thus giving rise to involving restora of previous cons

or of rebuilding in a manner comparable to the pre-exis types of buildings. Notwith-standing the fact that the same technical choice was exercised in both geographical areas, of strengthening the original walls with reinforced concrete frames, which was deemed to be safer, the ﬁnal results were diﬀerent.

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Recons addressed only the basic residen needs of the inhabitants in urban se ts en already characterised by abandonment, without any a en to exist-ing social dynamics (Figs. 5-6).

The 1997 earthquake in Umbria and Marche marks a turning point in technical inter-ven in masonry buildings, following the observa of a higher level of damage oc-curring in structures adapted to the previous technical speciﬁca a er the Campania earthquake. The parallel development of new ways of thinking, both with regard to the conserva of historical structures damaged by seismic and also with regard to the successive recons e outcomes following the Campania earthquake, has oﬀered further con o a change in methodology (Fig. 7).

The methodological change is characterised by the from pre-cons ed safety models imposed onto the exis situa (adapta to the survey of cons e vulner evaluated by analysis of the eﬀects of seismic on masonry buildings (damage mechanisms) and sing local interven (ameliora A change, there-fore, from pre-established resistant models to methodological processes that, thanks to the analysis of the buildings’ damage and vulnerability, allow for the choice of the best procedure to follow in accordance with local building systems 4_{(Fig. 8).}

At the same me, a move towards more flexible resistance tests than those previously adopted (limit state verifica and the possibility of opera through non pre-estab-lished mechanical models (FEM or BEM method), connected with local verifica (kine-ma analysis) related to possible da(kine-mage mechanisms, would allow for a be er calibra of the eff eness of interven espect to the buildings’ cons e features.

FIG. 5. New cons in Valle del Belice a er the 1968 earthquake. Oﬀ-scale design of Piazza Elimo in the new town of Poggioreale; and of the new mother church in Santa Margherita Belice.

FIG. 6. Recons a er the 1976 Friuli earthquake. On the le reuse of ancient material on the façade and, on the right, recons al type building.

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The studies carried out in this regard are not only aimed at analysing seismic vulner-ability on single buildings, but also that of an en e building block, es mutual interrela viour with respect to their exposure to open spaces.5

The approach illustrated above is also linked to the possible recovery of pre-modern seismic preven techniques, but only if their eﬃciency has been previously demon-strated (Fig. 9), and to the use of modern techniques, with respect to the need for com-pa eversibility (e.g. the use of recognisable steel elements) (Fig. 10).

These tr allow for the reevalua of past cons e technologies and con-sequently for the possibility of safeguarding the integrity of historical architecture as a synthesis of cons orm, rather than focus only on its exterior walls.

However, it is in the determina of the future purpose of historical small centres that the real strategic importance lies when considering conserva of the values ex-pressed by these centres. In the absence of a every evidence of the past will re-enter the cycle of natural dis The issue of conserva is unavoidably linked to the choice of a future use as much as to the safety requirement levels.

Choosing a such as that of a ‘park of ruins’ or of an ‘historical park’ could allow the maximum conserva of authen values and as well as reduced levels of safety require-ments, which could be applied only along the main paths or to be er preserved buildings used as recep services or museums. A similar hypothesis has been proposed, in a PhD thesis, coordinated with the CRPR,6_{for the former site of the town of Poggioreale in the Belice area.}

The urban area, which was abandoned a er the 1968 earthquake because of the relo-ca of the inhabitants to another site, s possesses remarkable remains of the original historical se t.

The temporal freezing of the se t at the of the seismic event cons es a special c or a possible re-use of the site.

FIG. 7. Ineff e consolida systems on buildings damaged during the 1997 earthquake in Umbria and Marche: a) lack of a c between the framework of the structure and the masonry; b) excessive inflex-ibility of the covering in concrete cement; c) ineff e reinforced steel bar for the strengthening of the walls. FIG. 8. Damage mechanisms and local interven o eliminate seismic vulner

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A ﬁrst hypothesis envisaged using it both as a training centre for experts engaged in conserva of historical buildings, as well as a site for training technicians and volunteers involved in preven diagnos and structural monitoring, vulner a and emergency management. Preliminary studies and hypotheses were developed on the ba-sis of the Sicilian Regional Risk Charter from the CRPR, and the Department of Theore al and Experimental Structural Dynamics of Palermo University’s Engineering Department, through the ng a block of buildings into a safe c as an experimental sample for the realisa of the future part of a project. Another proposal examined the division of the ancient centre into three zones, each with diﬀerent goals: a ‘park of ruins’ surrounded by greenery, a second zone used for accommoda and a third one des o be used for recrea

The current proposal instead is directed towards the philological restora of an albergo

diﬀuso, i.e. an Italian ‘virtual hotel town’, according to a project by architect Lelio Oriano Di Zio.

On the other hand, with the passage of the centralisa dynamics of the greater ci s and the depopula of the territory have led to the conges and socio-economic dys of the metropolitan centre, along with the deteriora of the general quality of life. Simultaneously, the development of a rising sustainability culture, interpreted as the recovery and valorisa on of exis ng resources and also as the best level of life-quality, can represent an opportunity for revitalisa on of small historical centres throughout the territory.

FIGS. 9-10. Interven with tr methods (on the top). Interven with recognisable compa

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Sustainable agri-food industries, handicra or cultural tourism could s te a return to inhabita Even if such can r ate resources more widely than the urban areas themselves, they would obviously require greater transforma in the interests of safety and in the adapta needed to establish pr e enterprises in the historical se ts. The a of these new would also require conne with main routes for historical centres sited on hills or mountains, or links to a network of towns in order to enhance the iden of places and of local products. Thanks to new communica on technologies, one would be able to maintain the typical characteris cs of products without having to depend on buyers who live in the same area of pr

Even in the case in which the rest of pr in certain zones may have fun due to the type of pr already exis on site, thanks to the modiﬁca of areas to promote pr , it also has the advantage of not being inﬂuenced by area/product iden a processes. Another e point is that the product and its use can become a symbol of mankind’s culture in a area over because it represents the autonomy of the people of that area and their capa-bility of naturally transforming local products on site.

The op of choosing a form of cultural tourism (albergo diﬀuso), i.e., the iden a-of the site as an ‘area’/’product’ is only possible in the case a-of those se ts that have maintained their inherited typical characteris o a high level.

Experiences of this type carried out in Italy, such as at S. Stefano di Sessanio in Abruzzo and at Sassi di Matera in Basilicata are characterised by the will to get the historical se t back to its most authen aspects while maintaining in situ all the historic recoverable material and reintegra missing parts with materials similar to those used

FIG. 11. The site of the old town of Poggioreale and a re-use hypothesis for diﬀerent areas depending on the damage c

FIG. 12. An image of the square of the old town of Poggioreale before the earthquake; current state; a project hypothesis for re-use as albergo diﬀuso. The project hypothesis ﬁxes earlier building transforma that did not conform to the site’s original historical homogeneity.

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originally. The inten has been to establish an image of homogeneity “by avoiding both building types that have been radically transformed and others that have been brought back to too e a phase”7_{from the per} _{e of the proﬁtability of the investment.}

The ‘area’/’product’ associa entails a risk of forcing the choice of technical inter-ven discarding the incompa ones by maintaining only the ‘coherence features’ of the area.

The albergo diﬀuso makes use of a network system that links to other remarkable places in the surrounding area. Consequently these surrounding areas te in the valorisa oject.

The rela between urban se t and surrounding area is made explicit in the rehabilita project of Poggioreale’s historical centre in the Belice Valley. The pro-ject in fact is governed according to a ‘Poggioreale values and quality chart’, which also calls for the conserva of the natural landscape (through such measures as a ban on installing wind turbines or solar panels near the urban se t, or er agricultural infrastructures in the surrounding ﬁelds that are not compa ea).

However, philological restora of an urban centre a er 39 years of use risks be-coming an opera of resurrec the ruins, i.e., reestablishing its integrity beyond its original history8_{(Fig. 12).}

Embracing the theme of the characteris iden of urban se ts or territory also connotes other types of experiences. In Sicily it has allowed the revitalisa of a number of urban se ts, such as the Late Baroque Val di Noto UNESCO site towns.

This type of iden characterisa en based on the maximum coherence to the concep could lead to the risk of freezing ancient sites, which are areas of histor-ical transforma that have developed in a natural ‘non-synchronic’ synthesis over into a deﬁned historical epoch, because of ‘product requirements’.

The choice of use also implies technical In fact, use and safety measures are strictly linked to a general restora project, directed to the conserva of the principle ‘authen alue’ of the site.9

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notes

1_{For the rela} _{ip between use value and the} other value in restora theory, I refer to Riegl, A., 1908. Der moderne Denkmalkultus: Sein Wesen und

Seine Entstehung. Vienna.

2_{For post-seismic recons} _{a er the 1693 Val} di Noto Earthquake in Sicily, the reference is a per-sonal research: Campisi, M. T., 2004. “Il terremoto del 1693 in Val di Noto. Permanenze e trasformazio-ni dei centri urbatrasformazio-ni”, in Storia urbana, ’Terr in Calabria e Sicilia fra ﬁne ‘600 ed inizi ‘900: piani e interven di ricostruzione. Saggi e documen-3_{On an} _{ismic building types used a er the} Cala-brian-Sicilian earthquakes of 1783 and 1908: Baruc-ci, C., 1990. La casa an a. Prot e breve ,

Rome, Reggio Calabria. For urban reconstruc on, see Oteri, M. A., 2014. “Riparazioni e trasformazioni di archite e danneggiate da terr in Sicilia e Ca-labria (1783-1908)”, in Aid Monuments – Conoscere

Proge are Ricostruire, Perugia 24-26 Maggio 2012,

Rome; Oteri, M. A., 2004. “Memorie e trasformazioni nel processo di ricostruzione di Messina dopo il terre-moto del 1908”, in Storia urbana, Terremo in Cala-bria e Sicilia fra ﬁne ‘600 ed inizi ‘900: piani e interven di ricostruzione. Saggi e documen ’, 106-107, 13-64. For the post-seismic recons a er the 1908 Messina earthquake, also Campisi, M. T., 2000. “La à della sicurezza: la norma a an -ca dopo il terremoto del 1908”, in ‘Ananke, 26/1999. 4 _{al discussion on an} _technical inter-ven on masonry building was illustrated in the guidelines of Na ee for seismic risk preven in cultural heritage on 14th July 1989, especially for the use of reinforced concrete stren-gthening on masonry building. In the same text the use of compa and reversible techniques is suggested, based on the ameliora approach towards local interven

Fundamental to the development of research are the works of engineer Antonino Giuﬀrè, introducing to Italy the ameliora approach in an strengthening. The most well-known quote: Giuﬀrè, A., 1996, Sicurezza e conservazione dei centri storici.

Il c , Rome-Bari.

5_{An interes} _applica _{is available in: Carocci,} C., Circo, C., 2013. “Le debolezze della à storica. Eﬀe sismici sul tessuto edilizio murario”, in Blasi, C. ed., 2013. Archite storica e t Protocolli per la conoscenza e la tutela, Milanoﬁori

Assago (MI).

6_{Cf. Guglielmini, R., 2007. “Poggioreale Old Town in} Sicily: Strategies, memory, knowledge and planning place”. Extract of Ph.D thesis on recovery and use of ancient contests, D.P.C.E., Department of Project

and Building Cons Available at: <h www.isprs.org/proceedings/xxxvi/5-c53/papers/ FPL003.pdf> [Accessed 14 March 2014]. CRPR is the acronym for ‘Centro Regionale per la Proge azione ed il Restauro’ (Regional Centre for Architectural Design and Restora a specialised structure for researches on cultural heritage, depending on Sici-lian regional government.

7_{Cf. Oriano Di Zio, L., 2009. “La sopravvivenza ed} il recupero dei centri storici minori viola dal ter-remoto, un evento possibile non un caso eccezio-nale”, in Stabile, F.R., Zampilli, M., Cortesi, C. ed., 2009. Centri storici minori. Proge per il recupero

della bellezza. Rome. 187.

8_{Interview with architect Lelio Oriano Di Zio} about the rehabilita project of Poggioreale’s ancient centre in Fondazione Federico II, Cronache

parlamentari, 2011. Available at: <h ww. ars.sicilia.it/DocumentiEsterni/Cronache/Crona-che_2011_002.pdf> [Accessed12 March 2014]. 9 _{Similar considera} _{are available in: Treccani,} G.P., 2006. “Apporto delle discipline storiche e della tutela alla valutazione di vulnerabilità di an edi-ﬁci’, in Menoni, S., 2006. La salvaguardia. Dei

va-lori storici, culturali e paesis nelle zone sismiche italiane. Rome. 174-175; and Fiorani, D., Donatelli,

A., 2012. “Restaurare e ricostruire: problema del dopo-sisma aquilano”, in T er journal 50, available at: <h goo.gl/tnHbC5> [Accessed 12 March 2014]. In this text: “Porre il tema della rico-struzione come meccanico di rifacimento di quello che esisteva o come libera palestra di sperimenta-zione c a appare fuorviante. Senza ritorna-re sull’abusato tema dell’alterna a fra il com’era dov’era e della riedificazione come r a con il passato, ci si limita qui a considerare come si tra di affrontare, più opportunamente, il problema sul piano più te del tra amento di una lacu-na urbalacu-na, modalità che pone nei gius termini i temi del rapporto – figura o, dimensionale, ma-terico – con l’esistente e della sincerità espressiva della ricostruzione. Tale approccio riporta anche la ques della torre di Santo Stefano a un metodo proprio del restauro, legato allo studio dell’asse o preesistente e del contesto per desumere da esso logiche figura e e di accostamento, non diversa-mente da quanto accade su singoli monumen (22) e non diversamente da quanto dovrebbe verificarsi per gli isola omple telvecchio Calvisio.”

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c as tel vecchio c al visio .

REMARKS ON THE KNOWLEDGE OF HISTORIC BUILDING FABRIC

REQUIRED FOR SAFETY AND PRESERVATION

Caterina F. Carocci

Università degli Studi di Catania, Italy c.carocci@unict.it

Intr

The experiment carried out on the small se t of Castelvecchio Calvisio oﬀers an opportunity for re on the possibility of preserving historic building fabrics and of living in or re-occupying the old houses in safe c It also underlines some of the most urgent themes regarding the fate of historical Italian se ts.

The case of Castelvecchio Calvisio (one of the historic towns hit by the 2009 L’Aquila earthquake) is offered as a model for general observa on historical centres dam-aged by an earthquake, and which were characterised by highly al c even before the seismic event. To the be er-known issues, such as those rela to a lack of maintenance (in most cases due to the gradual abandonment of the towns by the inhabitants), the effects of the earthquake drama ally add safety-related issues, thus making it even more difficult to define an framework aiming at re-use which is compa ble with the preserva on of historic urban fabrics (see the papers of Doglioni, Mirabella and Tocci).

The above-men set of topics and the actual outcome of the conserva that can be achieved by the project call on the input of various disciplines and specialisa However, topics and outcomes are heavily inﬂuenced by the central ques of ‘knowl-edge’, considered fundamental for the de of general strategies (rec of the values to be preserved) as well as criteria and interven echniques.

In this context, the present paper provides a brief overview of a fact-ﬁnding strategy structured around the fabric of historic masonry buildings and tested in many historic town centres of medium and small size. It also iden as the preferred object of the conserva project that urban fabric which is comprised of ordinary buildings: mostly family dwellings that are the essen fabric of the historic city, but rarely protected by la en badly reworked.

The historic house must be preserved even in the necessary muta that guarantee its use and the perpetua (or r a of everyday life. This premise inspires both the substance and the characteris of the fact-ﬁnding procedure in which the reality of the cons is inves ated through a ‘ al reading’, which tends to iden y speciﬁc characteris abric and the buildings that compose it.

A number of issues are of signiﬁcance, both as documentary data and as an unavoidable basis for the project: the rec of building types and their rela

in the forma of aggregates; the examina of cons techniques; and the re-cons torical ev y processes.

The fact-ﬁnding procedure seeks to extend the approach to conserva to include both the cons and structural aspects, and the aggrega and transforma processes that cons e the principal feature of the historic urban fabric (Carocci 2008).

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Although generally used in the context of ‘recovery plans’ or pilot projects at the urban scale, in recent years the methodology has been tested in post-seismic contexts, speciﬁcally a er the tragic Italian earthquakes of 2009 and 2012. The results of these experiments have highlighted new al issues for conserva and at the same have enabled us to acquire new data concerning the techniques and the material history of both the building fabric and the inﬂuence of the more recent transforma e

for safety and preserva occi, Circo 2013).

There is no doubt that the presence of a severely damaged urban fabric facilitates the inves a of local cons techniques (consider, for example, the collapsed that highlight the masonry work textures, facilita the analysis of masonry bonding). However, at the same the presence of collapses reduces the possibility of a reliable recons of the pre-earthquake c and paves the way for requests for subsequen abric which is already badly damaged.

The core of this latest re concerns the topic of the carried out subsequent to those caused by the earthquake (due both to technical a and suspi-cions about the eﬃciency and safety of the masonry structures) and is directly related to the case of Castelvecchio Calvisio.

In fact, even in situa e the collapses are limited in size and number, as is the case in Castelvecchio Calvisio, there is a real danger of widespread and unwarranted

dem-ener suit of safety’.

In this special context, the use of a fact-ﬁnding process that uses knowledge of the whole and its parts to search for essen overall and detailed meanings is proposed. This discipline leads to a considera of the interven and the material culture;

construc-techniques and the historical development of masonry organisms are integrated into a vision of restora ed by specialised sectors (Caniggia, Maﬀei 2001).

An inter-scalar fact-ﬁnding approach

the phases that make up the proposed methodological approach assumes sig-niﬁcance in the observa of a set of buildings or extended of the building fabric. The analysis of individual buildings and subsequent comparison (in the rec

of the repe of certain key features) deﬁne the inter-scalar rec approach. It in-cludes analyses characterised by substan erent tools and levels of in-depth analysis.

The ate inter-rela between the results derived from the diﬀerent read-ings creates a knowledge framework that is able to clarify, at the same the overall situa onserva alues of the building fabric being studied.

A number of factors are inextricably to local cons methods (strictly de-pending on specific factors such as, for example: the morphology of the area and the availability of materials); the general arrangement of the buildings (a study of building type and fabric); the details of the organisa of the elements and assemblies (a study of cons techniques); and the details of whole configura which have followed on from one another and changed also through capillary modifica The vul-nerability or resistance factors of the building fabric derive from this set of c

Building types and aggrega

The iden a of building types tends to highlight – in addi to the repe e-ness of distribu and dimensional aspects – the general cons methods (the

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recurring thicknesses of the walls, types of horizontal structures and roofs) and the rela-s between adjacent buildingrela-s (rela-shared longitudinal wallrela-s or prerela-sence of ambiturela-s). The repeated elements are thus recognised and this results in the de one or more ‘recurring arrangements’, which provide the synthe model for the house and its relevant variants (diachronic changes and synchronic variants).

Clarifying the conﬁgura of the whole and of the individual building elements – and, ﬁnally, their rela to each other in terms of c s reached – allows us to combine detailed knowledge of the local ways of living and building with the rec

of pr for degrada and/or damage. This then leads to an in-depth analysis of the second stage of the procedure expressly devoted to the analysis of con-s echniques.

In the elabora of a ‘chart of types’, to trace the ev of the gradually established building conﬁgura starts the phase of al re on the possible projects for a compa e-use of the buildings being studied (Fig. 1).

A simple observa of the building fabric in Castelvecchio Calvisio shows that the analysis should focus on inves a the organisa of the ﬁrst phase of cons

by c , for instance, a systema survey of the ambitus – both those s open and the occluded ones – in order to define their size and transforma or persistence (Figs. 2c, 2d). Moreover, a crucial theme seems to be the link be-tween the diachronic muta of the building type of levels and other recon-figura and the extension of the v al dis of the profferli with the

of corridors that tend to broaden the access points to the houses (Figs. 2a, 2b).

The results of these inves a could be an interes basis for design considera-related to the possible re-use of buildings both in rela to safety (e.g. the behav-iour of walls and proﬀerli in the presence of seismic and conserva (acceptable design muta s that can also guarantee the rec of the typological process and the physical preserva tructures).

Cons echniques

Through a change in the scale of observa the cons t elements of a house are taken into considera ﬁrst the walls, then ﬂoors, roofs and stairs. Here too the analysis proceeds by comparison, based on the overall observa of structural elements and on the survey of a number of samples chosen in order to represent the various

iden in the analysis. The purpose of this analysis is the iden a of the local cons e lexicon, and within that, the dis between good quality building and precarious cons (Fig. 3). This knowledge is essen for any repairs or integra which must be compa with conserva purposes and also eﬀ e in terms of safety.

In to the study of individual elements, the analysis of their mutual rela becomes especially important in seismic areas, i.e. the c ons through which the lo-cal cons technique takes on a structural meaning. en, in fact, the components also act as a constraint to the adjoining parts in the context of the whole cons

organism.

As a simple illustra of the above, we can examine how the cons technique present in the area aﬀected by the L’Aquila earthquake (and also observed, albeit more sporadically than in other centres, in Castelvecchio Calvisio) is characterised by the

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pres-ence of devices expressly designed to prevent the overturning of the external walls. A widespread pr in the historically seismic Mediterranean areas, the alloca of constraints designed to prevent the a of out-of–plane mechanisms (spurs, shoe or escarp walls, ﬂying shoring arches) is, in the L’Aquila area, primarily asso-ciated with a building technique. In this technique, the masonry texture is or-ganised to contain in its thickness dormant wood elements placed in rows and connected on the external face of the wall by means of small metal keys. Another frequently used feature, related to the seismic awareness of builders, is the use of trusses with systema c to the top of the wall that demonstrate an explicit inten to limit out-of-plane façade movement during an earthquake (Fig. 4).

Ev y processes

The recons of the ev y process is aimed at iden ying the muta that have produced the current stra d state of the urban fabric. By iden ying the chronology of the transforma in the aggregate, it is possible to posit the conjectural recons

of its ev y stages, i.e. the sequen cons steps from the first buildings to the present day. The al interpreta of the configura reached at each stage en provides crucial informa for understanding the current configura The reconstruc-of the ev y history is based on a sele of traces observed directly on the buildings, en those observable on the adjoining masonry walls of two adjacent buildings. The study of historical cadastral maps and the comparison with dimensional data aris-ing from the survey (differences between the thicknesses of the walls, the presence of tapers, added levels, et en confirm the assump y direct analysis.

FIG. 1. The ‘chart of building types’, which traces the gradually established ev of the buildings, is a al tool for the re-use of a restora on project (Post-Seismic Reconstruc on Plan of Fossa, AQ; drawing by architect S. Petrella). FIG. 2. Some characteris of Castelvecchio Calvisio concerning the global configura of the building fabric; some ambitus’ gaps located in different and spread throughout the urban fabric (c, d) and different arrangements in the eleva xternal masonry staircases and corridors (a, b; photos by the author). FIG. 3. The analysis result on the iden a cons e lexicon allows us to dis good quality from precarious cons finalising project choices as regards compa and needed interven (Post-Seis-mic Recons ossa, AQ; drawing by architect C. Circo).

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From an opera point of view, the comparison between the iden ev -ary stages can be aimed at dis the role that each transforma plays with respect to seismic vulnerability. In this way, it shows if the arrangement at a given phase is worse or improved when compared to the previous one. But besides purely structural aspects, this kind of analysis also provides food for thought about those aspects of the project more properly related to architectural choices, both in general (e.g. future

com-pa g. conserva terven

In the case of Castelvecchio Calvisio, this part of the fact-finding procedure might offer an opportunity to inves ate the nature and outcomes of any reconfigura between con units. This opportunity derives from the configura of the build-ing fabric, which is characterised by sbuild-ingle-cell buildbuild-ings and aggregated, as we have seen, by interposing ambitus.

In this context, the transforma single out directly the presence of an external stair-case and access balconies (o en added at the same me as the upper levels of the house).

Furthermore, such an analysis could explain some fairly widespread situa which are seen as anomalies on various scales: those consis of recent interven of repair and/or of volumes (presumably related to repairs/ a er the Avezzano earthquake); those represented by residual situa which are no longer understanda-ble (e.g. external stairs which do not lead to any entrance); those which realise, in diﬀer-ent ways, the closing of an ambitus, etc. (Fig. 6).

Interpre e synthesis and correla oject

The central point of the procedure can be found in the interpre e synthesis of the results, which is used as a guide for a project inspired by minimal interven In fact, the fact-finding approach, ted at different scales, provides a detailed summary of the issues iden by transla them into ques which the project must answer, both in terms of conserva compa and of the balance between the need to transform and the desire to preserve the formal, dis and structural aspects of the build-ing fabric. In , and with the aim of using the sugges from the fact-finding phase for the project, a result derived from more recent field experiments involves the recons of the c of the building fabric in the state immediately prior to the earthquake.

Both in the case of heavily damaged fabric, characterised by the loss of the built vol-umes, and in the case in which the fabric survived the earthquake without major collaps-es, the above-men recons is aimed at iden ying, albeit , the causes which characterised that manifesta of damage (Carocci et al 2010, Carocci, Costa 2013).

FIG. 4. All the sites of the seismic crater show a cons technique aware of the seismic problem, probably due to the 18th-century recons Diﬀerent kinds of an devices expressly designed to prevent the overturning of the external walls are recognisable in the buildings’ façades also in Castelvecchio Calvisio (photos by the author). FIG. 5. The ‘ al reading’ of a street façade allows us to iden y the muta of the ev y process that have produced its present stra state; moreover, the results en provide informa crucial to under-standing the current conﬁgura useful for the design phase (Post-Seismic Recons Plan of Fossa, AQ; drawing by architect S. Petrella).

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The importance of this recons e process for the project is clear: the compari-son between the pre-earthquake situa and the damaged c will highlight the strengths and weaknesses of cons conﬁgura and, at the same permit re erent design strategies (Fig. 7).

Rela ocess of safety calcula

The outlined fact-ﬁnding process and its results oﬀer the safety check procedure (man-datory in the elabora of the project), a synthe reading of the cons reality which iden the essen elements of seismic behaviour so that the cons of

FIG. 6. The spread anomalies can be understood in terms of muta of recasts realised in order to enlarge the houses, facilitate access, repair some or, ﬁnally, as ev y processes characterising the building fabric (photos by the author).

FIG. 7. Analysis of an aggregate conducted through the comparison between its state of seismic damage and that before the earthquake, showing a prior state of vulnerability. (Analysis of the historic centre of Casen , AQ; drawings by M. Costa)

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the model may be tested. In , the interpre e synthesis allows us to iden y the damage mechanisms alr ated by an earthquake (interpreta of the crack pat-tern in terms of kinema and those that could be ated (interpreta of observed weaknesses in terms of a lack of constraints capable of preven a certain movement). Numerical analysis is consequently possible with a simpliﬁed approach (Tocci 2003).

The speciﬁc weaknesses iden can also be transposed onto the cons of models for safety calcula (altera transforma subtr of the resistant of a wall). Finally, the detailed knowledge collected about the cons ele-ments (and about historical earthquake devices) will allow us to monitor their eﬃciency and determine, where appropriate, necessary localised reinforcement.

Rela ovement interven

There is a strong link between the fact-ﬁnding and design phases in the context of in-terven in exis buildings. This c is en actually le out in the opera -al deﬁni of interven techniques. A en is paid, for example, to an issue which is constantly present in the context of the restora site – that which relates to work on the masonry, the walls. These cons e the most important part of the cons

(in terms of quan and their cons e role in the built organism). As well as gen-era a deﬁned series of problems to be solved (recons eplacement of parts, strengthening of compactness, repair of cracks, restora of contact between elements), the opera framework oﬀers many interven techniques. These vary: in rela to their material content they can be seen clearly as conserva of the

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exist-ing, and are mostly less clearly defined in terms of masonry performance improvement. As far as masonry performance improvement is concerned, the results of the fact-finding analysis described above allow us to iden y, simply and with a strong focus on the ma-terial, the technique best suited to solving the problem iden both in terms of the specific c ns of its cons and material compa ty (Fig. 8). This applies at various levels to the problem in hand. Coming back to the building fabric damaged by the earthquake and characterised by the presence of collapses and the consequent need for a recons design, there is the problem of the technique to be used to rebuild the collap

The purely design considera that occur are once again enhanced by direct knowl-edge of the fabric and its detailed c In general, in cases in which it is possible to recognise the arrangement of the masonry cells, recons using the masonry technique will ensure greater eﬀ eness and compa , and avoid the intr

of mechanical imbalances due to diﬀerences in the rigidity and weight of the parts that are s ter Giuﬀrè 1993).

Although en challenged by the argument for the necessary ‘rec of the res-tora (and not advoca here that the external appearance of textures should be sim-ilar – the textures are almost never visible anyway), the use of masonry techniques clearly introduces into the discussion the ques of the quality of the project and its ex

Concluding remarks

This paper illustrates the approach to the study of masonry building fabric used for many years by the author in historical se lements and recently tested in post- seismic contexts. This approach derives from a methodology ted in three c e steps (knowl-edge, interpreta on, project) and is founded on two basic assump ons: (i) the belief that each cultural area is characterised by its own technical-construc on features, which give rise both to the overall structural conﬁgura of the system of the building and to the possibil-ity of deteriora and damage; (ii) the assump that interven techniques aimed at improving seismic resistance and simultaneously conserving the historical-cultural heritage of ancient architecture must be speciﬁed within the cons masonry.

The core of the methodology focuses on the fact-finding phase (knowledge step) in-volving the different scales that affect the conserva work. It thus builds a body of knowledge to support project decision-making, which – precisely through the c e phase – involves a detailed comparison with the material history of the techniques used to build those houses.

The con provided by this methodology in the examina of the c

of Castelvecchio Calvisio can be seen in the se up of a detailed inves a directly aimed at verifying the possibility of re-using houses in safety while preserving their ap-pearance and their historical material substance. We believe that the knowledge that can be acquired produces a close rela onship between the constructed object to be preserved and the pr of the changes necessary for its conserva – while im-plemen , of course, the principle of minimum interven We are aware that this reasoning does not solve all the many implica ons raised by the problem of historic town centres, but the a tude advocated here sees conserva on as paramount, even in st a frank reﬂe on the meaning that it must have in the context of historic masonry urban fabric.

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r eferences

Bartolomucci, C., Donatelli, A., 2012. “La conserva-zione dei centri storici minori abruzzesi c dal sisma del 2009: esigenze di riuso e ques di conservazione”, in Biscon G., Driussi, G. eds., Scienza e Beni culturali 2012, Marghe-ra-Venice, 101-111.

Caniggia, G., Maﬀei, G.L., 2001. Interpre Basic Building, Florence.

Carocci, C.F., 2008. “Analysis’s methodologies for consistent an interven on histori-cal masonry architecture”, in Seismic Risk

Earth-quake in North-Western Europe, Liège, 151-166.

Carocci, C.F., Ca ari, S., Circo, C., Indelicato, D., Toc-ci, C., 2010. “A methodology for approaching the recons of historical centres heavily damaged by the 2009 L’Aquila earthquake”, in

Advanced Materials Research, 133-134,

1113-1118.

FIG. 8. Interven proposals for diﬀerent quality of masonry textures a er a detailed analysis of the local con-s echnique. (Ancient Anavatos se t analysis, Chios, Greece. Study by C.F. Carocci)

Carocci, C., Costa, M., 2012. “Casen (AQ): A sei-smic improvement project for masonry buildin-gs”, in Jerzy Jasienko, J. ed., Structural Analysis

of Historical Cons , 2, Wroclaw, 1414-1422.

Carocci, C.F., Circo, C., 2013. “Le debolezze della ci à storica. Eﬀe sismici sul tessuto edilizio mura-rio”, in Blasi, C. ed., Archite storica e terre-Protocolli ope per la conoscenza e la tutela, Milan, 153-175.

Giuﬀrè, A. ed., 1993. Sicurezza e conservazione dei

centri storici: il c , Bari.

Tocci, C., 2003. “Modellazione meccanica sempliﬁca-ta delle s e murarie storiche”, in Ceradini, V. ed., Area Grecanica: Codice di a per la sicurezza e la conservazione dei centri storici.

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REDUCING THE COSTS AND PHYSICAL IMPACT OF STRUCTURAL

REINFORCEMENT AND SEISMIC PROTECTION OF ARCHITECTURAL

herit age : possible applica tions in c as tel vecchio c al visio

Francesco Doglioni

Is o Universitario di Archite a di Venezia, Italy doglioni@iuav.it

Foreword

Speaking about structural restora and seismic improvement issues, during the work-shop there was a strong affinity of opinion between Caterina Carocci, Cesare Tocci, Giulio Mirabella R and the writer of this text, members of the C group “Structural and building issues”. We tried to define a common on which our four interven while different, are based.

Our purpose is to confront in a coherent way the issues of the buildings’ structural stability, ﬁrst addressing the ques of reinforcement to counteract damage leading to structural instability, then repairs to previous damage, the c for shortcom-ings observed at the presen , seismic improvement.

Strengthening, repairing and comple the missing parts are considered as neces-sary pre-c omponents of seismic improvement.

Where possible, we also aim at devising interven that address tasks (e.g. repair and improvement). Therefore, we need to build a t link between sta strength-ening (represen a tr ﬁeld of restora and seismic improvement, which should rely on historically acquired experiences rather than ignore them.

We reckon (see also Cesare Tocci’s paper) that any kind of structural interven should be based on the same knowledge of the building as that necessary for the purpose of restora i.e. the study of the characteris features of the building and of the con-s techniques, as well as the understanding of phases of extension and altera of present and past layouts. This should let us maintain con ity in rela to the his-torically known behaviour of the building (Doglioni, Mirabella R 2011), the evidence of which must be deeply inves ated as the most important diagnos base, to weigh the impacts of necessary to improve safety, both for people and for the building itself: the logic is thus similar (not dis from) to that adopted by restorers and should be related to it. Caterina Carocci’s paper in this volume addresses this topic.

We consider that it is important to go further and develop a typological study of histori-cal buildings in diﬀerent cultural areas, ide fying their construc ve characteris cs (ﬂoors, walls and roofs) and past strengthening devices such as metal connec ons and e-bars, wooden piling, etc., the analysis of which is important in evalu ng the residual reliability and poten or use (see Caterina Carocci’s paper).

This core knowledge should be connected to the structural and seismic behaviour ob-served in situ, using the rela ship between architectural and structural typologies as well as the corresponding observed damage processes as a means of an the future behaviour of buildings that have not yet been damaged.

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In this way, we think of seismic improvement ﬁrst as a preven e measure against the diﬀering damage processes foreseeable by typological analogy and also against those actually in play.

Concerning the choice of interven we prefer and materials which are already part of the building, and to use contemporary materials and techniques in a ju-dicious and complementary way. Moreover, we are ready to use tr materials in new resistance schemes; or, on the contrary, to use innova e materials in tr

resistance schemes.

We would rather search for schemes that are able to collaborate with the historical situa both and modiﬁed, and to interact with the behaviour they have exhib-it , instead of depriving them of any structural role.

We would consider favourably interven such as the juxt of external and readily removable or easily reversible devices, accep a moderate visual impact, if this can reduce the physical impact on the building.

In this sense, the provisional systems used on buildings previously damaged by the seismic event, and which have undergone strong development in recent can be a useful point of departure in devising improvement interven s: they can be conceived as permanent preventa e works, devised in advance of any new seismic event, in a way that follows the usual post-seismic ra This would reduce both the physical impacts and the costs of improvement interven

We see structural modeling (see Cesare Tocci’s paper) in the role of a mechanical in-terpreta on of veriﬁed behaviours, rather than being the exclusive leading guide to future interven structural modeling could even be charged with the task of simula the possible behaviour of complex structures (for example, bell towers), without making it the exclusive approach. An appropriate approach should focus on understanding destruc ve mechanisms that have just been ated, and promptly counter them, as well as iden ying poten mechanisms arising from the form of each macro-element, and also those kind of speciﬁc vulner s which are due to the historical cons and

evolu-of the single building (see Caterina Carocci’s and Cesare Tocci’s papers in this volume). Thus, we think of calcula as the way to verify, quan y and evaluate the eﬃciency of strengthening devices in each macro-element, while yet conceiving them as described above, and adap them to the irr arising from the cons history of the buildings.

We therefore suggest an approach to ensuring building stability and structural safety that pursues con with the building, and takes into account its behaviour through-out thus redir its behaviour in a self-prot e way that is fully reliant on its own enduring c We also aim at developing innova – in terms of project, technology, computa and modeling – as an evolving work, following the knowledge gained through thorough inves a of the historical building, and r any form of abstr as well as any imposed and generalised interven technique (see Caterina Carocci’s and Cesare Tocci’s papers in this volume).

The need to reduce ﬁnancial costs and physical impacts of an terven

In of recession and scarce public resources, the restora of a building of mod-est value cannot reasonably require an expenditure on an strengthening that exceeds the economic value of the building itself.

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Beyond ques of economy, if it has also an historical-architectural value, an ethical and poli al issue arises: if public resources are not increased, the more any single inter-ven osts the less prot an be aﬀorded.

Therefore, reducing the cost of seismic-prot interven represents both a c of making reinforcement possible and of enabling the buildings to survive and be kept in use, and the se t of which they are a part as well. In to the im-pact of the earthquake, the situa is made worse if the building was formerly neglected and situated in a half-abandoned town.

More generally nowadays, cost r represents an imposed prec for an eﬀ e and widespread seismic prot al heritage.

On the other hand, most an reinforcement techniques of today are expen-sive and impact strongly on the building, especially when its character and authen rely on old wall surf en happens in small historical centres.

Within the proﬁle of conserva it is therefore necessary to seek a er interven that are inexpensive and low-impact.

This would suggest a change in approach, moving away from interven which are usually conceived as directly applied to the building itself, and towards using at least

par-ect reinforcements and external strengthening. Developments in the ﬁeld of provisional post-seismic interven

Furthermore, over the past ten years the use of new materials and opera tech-niques has been changing the pr in post-seismic provisional interven in a profound way: wooden resis scaﬀoldings were en replaced by plas or metallic bindings, reinforcing strip s placed on rigid external dis etaining elements. We think such devices could be adopted as de e reinforcements, once they have been properly reﬁned, though they would keep the main features of a provisional work: a high degree of reversibility, low impact and reduced costs.

On the one hand, tr methods such as restraining rods, which appear effi-cacious in terms of cost and impact, can achieve be er performance through using new materials of equivalent At the same the degree of improvement is s lim-ited by reduced strength at the point of applica the plate fixed to the wall. The local punching effect arising from the modest resistance of the masonry is a factor in

w materials.

Seismic improvement through ‘stable provisional interven

The applica of diﬀerent external restraint elements is suggested as a seismic im-provement interven that will counteract damage mechanisms, incurring lower costs and with lower impacts on old buildings, while at the same reducing the visual im-pact on the context. Of course, visual imim-pact cannot be completely avoided, but the ap-proach must ate it as much as possible by reconsidering the kind and number of extraneous objects that can be acceptably juxtaposed alongside the external walls to

pro-t ontext.

Even though the purpose is preserva on, this necessarily brings about a change in the image of the building and of the building’s context.

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Repair of exis st step in the strengthening interven

The ﬁrst stage of the strengthening interven aims at comple missing parts and making up for lost resistance c The primary goal is det as they are en hidden – the second stage is that of remedying them.

As concerns lost c we can just cite the case of wooden piles or wooden ring-beams, the la er inserted in the wall and en connected to external metal anchors. Rarely detectable from outside, being situated longitudinally in the middle of the wall during con-struc on, their close proximity to the corner (25-30 cm) is their only detectable sign.

The wood inside the wall en undergoes total decay, making this very important reinforcing system ineﬀ e.

Some pictures taken in the north of Veneto show the big voids which were le by the decay of the ancient wooden members (Fig. 1) and their by now ineﬀ e metal heads (Fig. 2); similar wooden members exist in Castelvecchio Calvisio, revealed on the outside

b tal anchors.

But their eﬃcacy had already been ques as we can see from the later iron an-chors, corresponding to al s, which were put on the inner side of the façade wall (Fig. 3).

The fact of their being difficult to detect, repair or replace counts against the inner wooden ring-beam, whose residual efficiency is also hard to appreciate. Thus we have to find an equivalent kind of compensa one that has a similar but a different form of cons

During some interven elsewhere, an opportunis recovery of this ancient and lost device allowed us to put metal ods into the void le by the lost beam (Figs. 4-5-6).

Where the original inner ring beam was helping to connect walls and ﬂoors, we built a new metal or wooden ring beam just at the contact between wall and ﬂoor, steel anchors on the outside (Fig. 7).

We consider this as a ask interven whose general validity goes beyond re-placing inner wooden elements that have been lost. Actually, such an interven both

repairs a shortcoming of the al cons arising from its physical decay and

coun-teracts the overturning mechanism of the façade, as well as the related phenomenon of

pulling beams out from the wall.

Furthermore, it lets the wooden ﬂoor (reinforced where possible) achieve its task of transferring stresses and dis y supports.

A sort of ‘ bond-stone’ eﬀect emerges when the inner metal or wooden element is connected to some even thin and uncemented rods, crossing the wall and with a small metal distribu on plate outside. That is an element linking two walls which usually move – and collapse – separately, in when in stonework like that in Castelvecchio Calvisio. This kind of approach can reduce or even cancel the need for such expensive and strongly

terven mented drillings and widespre to the wall. Factors weakening the building

All buildings have some weaknesses in terms of structure and state of conserva which results in a loss of efficiency when compared to their structure and integrity of cons This arises from deficiencies in repairs, from previous damage, inherent discon and altera inadequate interven and physical decay. Inadequacies of cons compound these deficiencies. These factors and c

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gradual-ly prejudice the correspondence between the building and its original structural concept, which is en diﬃcult to recognise; put more simply, the link between the architectural and typological layout and the corresponding structural behaviour is weakened over

The point of is the focus on neutralising the discon repairing gaps and missing fabric (see Mirabella R paper) and on se a proper level of mainte-nance. This last task, in ancient buildings, is usually undertaken through restora

The need to adapt general criteria to local building cultures: the case of Castelvecchio Calvisio Our general approach also requires a deep adjustment to diﬀerent kinds of situa each trying to be complementary to what exists and r ng the of any standar

Thus, Castelvecchio Calvisio is a very interes case from two per es; on the one hand it portrays an extreme example of co-exis c of preserva and neglect, and on the other it displays a remarkable coherence of urban structure and con-s echniques.

With regard to the ﬁrst per e, the extreme example of co-exis c of pres-erva and neglect, exacerbated but not caused by the earthquake, is rare and precious

FIGS. 1-2. The ineﬀ e metal head of the wood-en ring-beam which had bewood-en embedded within the wall, and which is now completely lost. Villa Tomi-tano, Feltre.

FIG. 3. The external metal head, but without any key, from a probable wooden ring-beam originally set into the wall, and the keys of two later inner -rods, which were put alongside the wall. Castelvecchio Calvisio.

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FIGS. 4-5-6. The external hole of an ini metal key (Fig. 4), the empty space inside the wall le by the lost wooden ring-beam (Fig. 5) and a new rod inserted, using that hole (Fig. 6). Port’Oria, Feltre.

FIG. 7. A metal ring-beam with c to the heads of the beams and to the walls. Casa Fornezzi, Feltre.