Pittaluga Daniela, Stagno Gerolamo (Genova, Italy), Forte Riccardo, Secondini Linda(Paris, France), Gelvi Silvia, Bruzzone Anna (Genova,Italy)
Historic truss and framed wooden structures in Liguria: Diagnostics of condition, preservation VkontakteFacebook

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Summary: For centuries framed wooden structures, being one of the basic construction systems, have been playing a crucial role in the evolution of wood use in civil engineering. Man has been skillfully using this natural material in various contexts and architectural solutions since the primitive age. In Liguria truss structures have been widely used in historic buildings for construction of floors, roofs, stairs, and false vaults. Framed structures were used in a less degree. They attracted the attention of builders only in the end of the 19th century thanks to large trade fairs. These structures, alone or in combination with other materials, turn out to be helpful for the industry and production cycles providing interesting solutions in the housing and tertiary sectors, in Liguria as well.

Keywords: truss wooden structures; framed wooden structures; architecture; conservation; Liguria; Cultural Heritage;

Аннотация: Исторические стропильные и каркасные деревянные конструкции в Лигурии: Диагностика состояния, сохранение. На протяжении столетий каркасные деревянные конструкции, являясь одной из основных строительных систем, играют ключевую роль в эволюции деревянного жилищного строительства. Начиная с первобытной эпохи, человек научился умело использовать этот природный материал, найдя ему достойное применение в различных контекстах и архитектурных решениях. В Лигурии стропильные конструкции широко применялись в исторических зданиях для сооружения перекрытий, крыш, лестниц и фальш-сводов. В меньшей степени использовались каркасные конструкции, которые привлекли внимание строителей лишь в конце 19-го века, благодаря крупным производственным выставкам. Эти конструкции, одни или в сочетании с другими материалами, приходят на помощь индустрии и производственным циклам, предлагая интересные решения в гражданском строительстве и сфере обслуживания зданий, в том числе в Лигурии.

Ключевые слова: стропильные деревянные конструкции; каркасные деревянные конструкции; архитектура; консервация; Лигурия; культурное наследие;

1. INTRODUCTION

1.1. Wooden frame structures

What are wooden frame structures ? What are the most widespread areas in a context such as Liguria where in the past the wood has apparently had a very limited use? Where are the potentials? Where are the limits? And above all, what are the precautions to be taken for their conservation?

These are the main questions we started from with a targeted research in 2015 [1] . Within this broader research we included two dissertations, still in progress, at the Department of Architecture of the Polytechnic School of Genoa; in particular we involved of the area of architectural restoration and technology.

The first of the two thesis, prof. Daniela Pittaluga, correlators prof. arch. ing. Giorgio Mor arch. Gerolamo Stagno, is carried out by Linda Secondini and Silvia Gelvi. It was aimed to operate a first census of wooden frame structures in the Ligurian area.

Liguria has manly used the stone for its construction, more rarely the brick and much less the wood. The wood, in effect, in historic buildings was used mostly for the structures of horizontal elements, for roof structures and window frames. One of the questions to which an answer has been sought with the thesis was to verify the actual heritage of wooden frame structures in this territory [2] .[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

The second thesis, prof. Daniela Pittaluga, correlator arch. Gerolamo Stagno is carried out by Anna Bruzzone. It had the aim to investigate the specific degradation phenomena of this type of structures, highlighting the particular vulnerability and suggesting appropriate remedies and desirable maintenance [3] .

2. Notes on the wooden homes of the late nineteenth-early twentieth century in Liguria

2. Historic buildings framed in wood instrumental methods of knowledge

The developed methodology for a systematic and in–depth knowledge of the timber frame construction also investigated the status of the materials through instrumental tests can identify specific points of vulnerability of the buildings themselves.[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

Taking into main consideration as one of the critical elements of the wood that generates degradation is the humidity and particularly the wet systematic chin that generates first degradation xilofago with moisture of the material up to 20% thereafter mycotic over 30% up to the complete loss of each mechanical strength with rot, have developed surveys on some significant points of repeating them systematically buildings where possible for each case examined.

The methods applied still ongoing include.

The knowledge the species inherent conducted with samples using micro tree cores extracted using mechanical increment borer then analyzed with a player of the Tree Core Reader section also useful to determine along the radial sections conducted other degradation diseases.

The determination of the electrical resistivity method inherent in the percentage of moisture.

The determination of surface density surface with hammer Pyoldin wood zone where more develops woodboring degradation and then mycotic.[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

The deep measuring always conduct density electronic drills.

Investigations on identified as the grounding of the wooden structures (ground construction area and the area of foundation elements in elevation plane) and (nodes uprights transoms) involved healthy and degraded areas and can then establish a local relationship between the individual and then buildings.

In particular, it is also proceeded in the presence of coating treatments and were also considered secondary panel elements and collaborating.

The buildings examined represent a constructive champion also durability being mostly built with more than 50 years of life even when subjected to maintenance activities for which you are trying to draw up tables.

The sample of buildings is seen in the progressive growth of cases surveyed that are periodically inserted.[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

This investigation developed on buildings even closer to the water, however, differentiated typological situations ranging from contact with the water itself on the beaches to see house near to the seaside buildings located a few kilometers; Also this exposure will be considered in final evaluations on critical points as their exposure.

The set of data collected include the Historical Archive of documentation as available will provide a complete picture on building types on their technologies and from the point of view of the individual elements also of the links between them and the material including durability treatment.

From this amount of data it is assumed to process the experiencing both a first Inspection Protocol also differentiated for the kinds to be applied case by case basis.

In most urban and territorial scale is expected to achieve a reference Electronic catalog which also includes the drafting of a grassy code for the conservation of buildings and their restoration.

3. Most Relevant Categories And Experimental Sheet

In the Ligurian area there’s no cultural heritage about wood bearing structures, however we located a considerable number of wooden framed buildings constructed between the end of the 19th and the beginning of 20th century. These were the years of the International Expositions in which new construction models were designed and brought to many areas, included Liguria.

We defined 3 categories:

There is an isolated case of a waiting room made by a simple frame structure with timber walls, in the Rigoroso Station, a village in Piemonte.

There’s also a single funicular wood’s terminus that connects the historical city centre of Genoa with the heights at the back. It is a building composed by two blocks crossed by the rail.[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

A dense network beams, covered by a corrugated sheet, arm the roof that connects all these three areas.

Experimental sheet

An experimental sheet was made to be a relevant instrument to understand the building technique used for the analysed edifices. Moreover it tries to underline the analogies between them. Our aim is to create an experimental practical code for frames, in order to systematically classify and store the building procedures.

Many of the buildings are inhabited or in use and it was a limit, as the characterizing elements couldn’t be analysed with an invasive approach.

We reserve therefore a chance to provide constructive assumptions as compatible with the visible structure.[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

This sheet is divided into two sections; the first one is at a macroscale level, while the second one has a microscale focus, pointing out the technical details.

In the first section we can find the building general information, included address, owner, land-register data and ground features.

In fact our specific attention is directed to the external shape and the way it is perceived.

In the second part, we move on to a deeper analysis of the building, making a difference between the elements of the resistant structure and the envelope ones.

In the resistant structure we analyse:[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

We then analyse the envelope system, meaning the elements that compose the internal and external frame walls. We describe the characteristic, the material and its arrangement.

Finally we describe the load–bearing structure, the numbers of its elements and the characteristic of its joist. You can find a summary table at the end of each chapter. There are also a special area for notes and drawing useful for the inspection report

In the last chapters you can find details about the wood quality–characteristic and a reference to the possible construction wear.

4. Monitoring of conditions

After the identification of a considerable number of wooden framed structure buildings, in the territory of Liguria, it’s basic for us to investigate the state of conservation from the structural point of view, with high regard to the durability of the materials put in place.

From this requirement, the need of patenting a fast, simple and efficient method to allow also a not experienced operator, to have a basic knowledge of the artifact regarding both the technological state of the building and the conservation of the materials.

To provide this task, a filling paper is still being developed.

The still under study tab includes two parts; a preliminary one investigates the state of conservation of the building technology and investigates the elements’ connection considering the building as a system, the second is more specific and investigates the state of conservation of every single wooden element.

For the creation of the schedule (card/dossier), it was decided to investigate a selected sample of four buildings, each of them can be placed inside a standardized type identified in this study.[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

By a first sight–classification of timber elements and by instrumental diagnostic tests (percentage of humidity inside the wood, material hardness, essence) the degradation phenomena results very similar for every building.

First common data to all inspected buildings is that the essences (wood) they are made of are never native, but they come from other regions; 90% of the timber belongs to the family of conifers, the most common species found are spruce, silver fir and pine. This phenomenon highlights how the technology of wooden truss construction was imported in to the region and it also explains why some renovation or restoration interventions to these buildings has often been degrade bearer. The lack of knowledge of the subject by some local craftsmen has made possible that incompatible materials such as wood and concrete were often combined in the buildings; this habit has produced devastating effects on the wood that show in the presence of rot, decay and insects. The most deteriorated elements are the ends of the beams in pillars, where they stand on the floor and the surfaces of the same beams where they are juxtaposed to the walls.

Proximity to the sea, summer heat and very wet air’s temperature, are not sufficient to cause material degradation; but added to a lack of maintenance works or to careless conservation interventions, this climate conditions may be dangerous to the wood durability.

The following are some average data obtained by instrumental surveys.

Average humidity of timber inside the buildings results less than 20% (a good result), in a range between a minimum of 10% and a maximum of 37%.[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

Mechanical condition of material is generally good, the toe of the wooden hammer seldom exceeds values of 20 mm except in deteriorated areas where values exceed even 35 mm.

5. Conclusions

One of the first results from the research that has taken place in Liguria in relation to the presence of buildings with wooden frame structures was as follows:

Reference

[1] D. Pittaluga, “Elementi costruttivi in legno: solai e coperture. Criteri e tipologie del costruire storico ligure: conoscenza per una datazione”, abstracts in “Il legno tra passato e futuro”, Campoligure January 25th 2013, ed. Vitali e Ghianda, Genova, p.8.

[2] D. Pittaluga, “Legno, degrado e restauro” in Progetto Colore, ed. Tecniche Nuove, Milano, anno 45, n. 3, 2011, p12. [3] D. Pittaluga, “Stratificazioni lignee: problemi di individuazione, interpretazione e conservazione”, in Atti del Convegno di Scienza e Beni Culturali, Bressanone 2009, pp. 95–106.

[4] D. Pittaluga, “Questioni di archeologia dell’architettura e restauro” ed. ECIG, Genova 2009.

[5] Luciano Patetta, L’architettura dell’eclettismo. Fonti, teorie, modelli 1750–1900, Milano, Città Studi, 1991 (collocaz. Biblioteca Fac. Arch. C.1185. Disponibile anche alla Bibl. Berio – collocaz. 724.5 PAT).[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

[6] Maria Flora Giubilei, « Materiali per una storia dell’architettura neogotica genovese di fine secolo », in Rossana Bossaglis, Valerio TERRAROLI (a cura di), Il Neogotico nel XIX e XX secolo, Milano, Mazzotta, 1990, vol. II., pp. 59–67.

[7] Tito Tuvo, Sestri Ponente memorie e ricordi, Genova 1987 (per le foto dello stabilimento industriale Piaggio a Sestri Ponente – disponibile presso la Biblioteca Berio, collocaz: Gen. B.4232), oppure consultabile presso la Biblioteca Provinciale dei Cappuccini di Genova (collocaz: 1LIGTER 110 34).

[8] “Primo Convegno Nazionale Legno Lamellare Norma e Progetto” Venezia, 08/10/1999 I. U. A. V. – I. T.L. CNR Bolzano : Relazione presentata : Diagnosi e consolidamento statico con legno lamellare in solai lignei storici – in Atti

[9] 21–22/01/2005 Facoltà di Ingegneria di Genova Convegno Lignea Materia : Organizzazione del Convegno Comunicazione sulla “Diagnostica delle Strutture Lignee”

[10] Collegio degli Ingegneri della Toscana – Università di Firenze : DIRES : International Conference on the Conservation of Historich Wooden Structures – comunicazione in collaborazione “Sistemi di calcolo per collegamento legno–calcestruzzo mediante connettori metallici a secco” Firenze 2005[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

[11] AIPnD : 13° Congresso e Conferenza Nazionale sulle Prove non Distruttive Milano 2009 comunicazione “Le volte a centinatura in legno e camorcanna La diagnosi dello stato di conservazione della volta dell’aula della Chiesa di San Rocco di Principe di Genova : il degrado invisibile dalla diagnosi all’intervento di conservazione soniche su edifici colpiti da eventi sismici. ”

[12] Classificazione del Legno in Opera Normativa e criteri di conoscenza sperimentale diagnostica In Convegno Il legno tra passato e futuro conoscenza, conservazione, costruzioni, design, Campo Ligure 25.01.2013

[13] The wooden roof of Banessa e Skendulate in Gjirokastra, Albania: the role of diagnostic test campaign in the structural safety evaluation In SHATIS 2013 2° International Conference on Structural health assessment of timber structures 4–6/09/2013 Trento (italy) S. Podestà,F. Pompejano, G. Stagno

[14] Convegno Verona 2013 “Legno & Edilizia” Corso di Formazione Classificazione a vista del legno massiccio, controlli in cantiere non distruttivi

COST 2014 The durability of wooden structures in the marine environment – The vehicular bridge over the Torrente Branega – In the buffer zone of Genova Pra The Maintenance Plan ; Diagnosis – Gerolamo Stagno Giovanni Damonte Chiara Tartaglia Alberto Carlascio Emilio Costantino[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]

[15] The “Gothic house” in Arquata Scrivia (Italy): costructives details and seismic assessment of a timber framed masonry structure. Cattari*, S. Lagomarsino, R. Vecchiattini and G. Stagno Hearth 2015 “°Ediz Lisbona Nov 2015”.

// Системный подход к сохранению памятников деревянного зодчества
Составитель А.Е.Косканен
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