In order to limit the damage caused by a misplaced

An Italian approach to the preservation of

historical monuments

S. D'Agostino, G. Frunzio

Centra Interdipartimentale di Ingengneria per i Beni Culturali,

Universita 'FedericoII', 80121 Napoli, Italy

Abstract

This paper deals with the contribution that engineering particularly structural

engineering, can bring to the preservation of Italian monumental heritage. A

more critical cultural strategy is highlighted, which is based on the historical

materials used in the finished monument. The paper also shows how various%

institutions have managed to cooperate in joint research, even through the

objective difficulties in interacting with professionals and private enterprises.

1 Introduction

Italy has suffered a long series of earthquakes over the last twenty years.

The earthquake that hit the Friuli region in 1975 and the one that devastated vast

areas in Southern Italy in 1980 are of particular note.

Historical monuments in these areas suffered serious damage: from the

extensive archaeological sites of Paestum, Pompei and Herculaneum to the range

of monuments and archaeological sites dotted around the region.

In all this, structural engineering has been called upon to carry out an

important task in reconstruction and restoration work. Unfortunately, however,

it has faced this task with the usual methods used in today's residential buildings

and using construction techniques and materials that are particularly intrusive: not

in line with ancient techniques and materials, and irreversible.

Transactions on the Built Environment vol 15, © 1995 WIT Press, www.witpress.com, ISSN 1743-3509

90 Architectural Studies, Materials & Analysis

In order to limit the damage caused by a misplaced strategy, the Ministry

for Cultural and Environmental Heritage set up in 1984, a "National Committee

for the preservation of earthquake risks of historical monuments". For the first

time, structural restoration work was seen in an interdisciplinary light, given the

presence of structural engineers, geotechnicians, architecture historians,

architects and restorers in the Committee. The Committee has done much work

over the last ten years drafting some fundamental documents, in a first phase,

than can give guidelines to safeguarding historical wealth. It has also financed a

series of pilot projects which peripheral agencies of the Ministry have been able

to develop. It has, finally, stipulated specific conventions with many Italian

Universities to finance a complex research strategy.

This action has stimulated a more reasoned approach to the preservation of

historical monuments which has involved other engineering fields from

geotechnics to technology, and tomaterial and plant engineering. Thus, the first

Centre of Engineering for Cultural Heritage has been set up at the Faculty of

Engineering of the University of Naples "Federico II".

Here follows an outline of the work done so far.

2 The work of the Committee for the preservation of

earthquake risks to Italian historical monuments.

2.1 - The documents drafted.

In 1987, in Venice, the Committee held the first seminar about the

preservation of earthquake risks to historical monuments !. This gave the

opportunity to illustrate the Committee's cultural lines through presentations and

a mass debate, and which can be summarised as the following with reference to

structural restoration work:

- homogeneity in materials and construction techniques;

- reversibility.

"Recommendations relating to interventions on historical monuments of special

typology in seismic areas", drafted by the Committee in 1986, were also

presented to the scientific community.

These Recommendations specifically emphasise the unsuitability of normal

seismic standards used in modern construction work for archaeological sites and

monuments, underlining the absurd concept of seismic adaptation for these


Architectural Studies, Materials & Analysis 91

complexes. It is impossible to think that old cathedrals, buildings and even

castles, forts and walling, that have withstood the rigours of centuries, should

need to be "adapted" to seismic activity when their stones bear testimony to the

seismic events that have occurred in the area over the years and which today

represent tangible proof of man's need to leave a legacy of his own history and

civilisation. These monuments, which have been abandoned many times over

and brutally treated by man's actions, must be seen in the light of their structural

nature - as much in the behaviour of their ancient materials as the very civilisation

of man that put them there. They need continuous and programmed maintenance

work that will "improve" their resistance to earthquakes; with respect to the

monument's material history, this maintenance must be carried out with those

traditional materials and construction techniques that have enabled it to withstand

the test of time for so long.

Once having established a cultural strategy, in 1989 the Committee then

saw to drafting "Directives for setting up and carrying out restoration

programmes involving antiseismic improvement and maintenance work in

architectural complexes of historical and artistic importance in seismic areas".

These directives provide precise guidelines on the consolidation of

foundations, walling, columns, arches, vaults and other structures, even

prescribing particular action for archaeological ruins. For example, they

underline the unsuitability of reinforced concrete foundations when restoring

ancient monuments. These foundations will alter centuries old ground layers,

destroy a layer which in itself is archaeological, and turn a direct foundation into

an indirect one, thus sharply altering the structure-foundation relation. For the

sake of brevity, we shall only mention this example and refer readers to the

Directives ] for a complete picture.

Another document presented in Venice concerned the particular behaviour

to adopt in case of earthquake in order to safeguard historical monuments.

Unfortunately, a great deal of cultural wealth has been seriously damaged and at

times destroyed by hurried interventions soon after earthquakes. The same also

holds for demolitions and propping of monuments carried out following only

criteria of urgency. One must also bear in mind that very serious circumstances

can see the involvement of the army and ad hoc volunteer groups that do not

have any specific grounding in the field of national monuments.



2.2 The development of a new culture and the

research conventions.

The Committee's work has thus consisted of creating documentation for

the Ministry of Cultural and Environmental Heritage. This work, though,

assumes a great research contribution by many structure specialists who have

based their cultural strategy on two principles:

- studying the monument's material history and centuries-old development;

- being aware that man's construction culture has developed over centuries

outside a mechanics vision of reality, and that the foundations of construction

science were based on an analysis of geometric relations and a profound

knowledge of materials.

Over the last decade, this approach has become rooted in Italy and many

scholars systematically inform the international community of their research

resultsP-16], even if it is difficult to create a vast arena for exchanging ideas.

It is precisely for this reason of awareness of the need to deeply revise

relations between structural engineering and historical monuments that the

Committee has taken the lead, through massive funding by the Ministry of

Cultural and Environmental Heritage, to stipulate dozens of research conventions

between the Ministry and Italian Universities.

All the conventions have been formulated in a single programme with the

aim of "protecting cultural assets subject to seismic risks". The programme has

been formulated taking into account numerous cultural interests ranging from the

history of architecture to the theories of restoration work and the mechanics of

structures. Here follows a summary of the four research orientations:

Research orientation 1: Basic characteristics and typology of the sites;

Research orientation 2: Vulnerability;

Research orientation 3: Behaviours and calculation methods;

Research orientation 4: Intervention technologies.

Each research orientation is aimed at particular later objectives.

After some bureaucratic difficulties due to delays in financing the venture,

the programme is now in full swing and is expected to finish next year.

Moreover, the research results are going to be available in a series of volumes

edited by the Ministry for Cultural and Environmental Heritage.



During the research, we realised that some integration was necessary. For

example, a vast research programme was found to be necessary for research

orientation 4 for characterising the mechanic behaviour of construction materials

traditionally used in the various Italian regions for building historical

monuments.

Finally, alongside the conventions stipulated with Italian Universities, the

Committee has also financed some pilot schemes carried out by peripheral

agencies of the Ministry on emblematic monuments.

2.3 Exemplification of a research orientation.

2.3.1 Experimental research on construction

materials traditionally used in Italy.

Large-scale detailed research was first done on the knowledge of traditional

construction materials and technologies used in the various Italian regions in

building historical monuments. The impelling need thus came to light to carry

out systematic research in the mechanic, physical and chemical properties of the

materials used in building historical monuments.

These materials had for a long time been neglected by experimental

scientific research in the structural engineering field and thus the significant

scientific contribution to material history in architecture was overlooked.

The limited use of these materials in modern construction and the lack of

any real scientific interest in ideas of recovery an preservation of materials have

also contributed to the neglect of actions aimed at drafting laws and rules in order

to understand the various properties of these materials; at present, there is no

feasible system of regulations for these manufacts.

In order to define the mechanic characteristics of construction materials and

the specific calculations, such a system is developed on three levels.

The first is the national level and is the oldest. As regards walling

materials and wall structures in Italy, it is often very basic and sometimes totally

insufficient (there are no specifications for determining resistance of walling; the

regulations for calculations of structures undergoing seismic activity includes

walled buildings with simple qualitative guidelines).

The second level in the regulations, currently under study, involves the

body of documentation from the European Union. In view of European



integration this will constitute a set of joint regulations for the member states.

The European Committee for Standard Regulation (CEN) provides indications in

order to determine the mechanic characteristics of materials. In particular, the

Committee "CEN/T 125 - Masonry" refers to walling materials, its components

(mortars, brickwork, artificial and natural stone) and the structures they go to

make up. At the same time, Eurocode 6 provides calculation indications for

structures in masonry. The need to have an international system of norms has

been felt in Europe since the early 1970s in order to avoid the problem of

different calculation methods used in public works.

The international picture is completed by the ISO regulations. The ISO/TC

179 Committee, in particular, deals with the definition of simple criteria for

designing buildings of up to two storeys and relative structures.

These layers of regulations should represent a future specialisation in

norms from the general aspects to the specific needs of individual countries. The

German regulations (DIN), for example, already include references to European

regulations (CEN) where they exist.

Setting up a body of regulations, particularly at the international level, needs

further research - both individual and in committees - in order to disseminate the

experimental results under the form of "recommendations".

Moreover, the variable nature of materials and type to be found even only

in Italy needs a flexible system of regulations adaptable to various applications.

Alongside this type of literature there is also that of developing countries

that have to adapt regulation on the industrialised nations to their own needs, and

also set up control mechanisms for materials that are no longer used in the West.

This situation, which has only recently started to attract attention in

international scientific circles, still does not see the specific inclusion of historical

walling and there is no study of historical materials, if not by the RILEM 131

Committee ONM (Old and New Mortars: ancient mortar and mortar for

restoration). For the analysis of resistance and material characteristics, reference

is made to the overall structure, underestimating certain problems such as those

linked to the heterogeneous nature of the materials used and ignoring some

aspects of mechanic behaviour. When we deal with testing of materials in

historical buildings, we must bear the following problems in mind:

a) Tests on sample materials taken from a building: methods of sample

collection, sample size, testing methods, measurement methodology of the

required parameters.



b) Tests on new materials, from quarries in the case of stone buildings: selection

of materials to best match those used in the building studied, sample size,

testing methods, measurement methodology of the required parameters,

possibility of comparing results with samples taken in-situ.

c) Tests on samples of masonry taken in-situ: assessment of sampling feasibility

(in the case of concrete core masonry, it is nearly always impossible to carry

out), sample size, testing method, measurement methodology of the required

parameters.

Moreover, it is essential to define:

- the nature of significant tests;

- the sample size to standardise

- the number of tests to be carried out to obtain a reliable result on a paper

statistical basis;

- the testing equipment;

- all the physical parameters to be assessed and the measurement range in which

these parameters are to be assessed.

In order to make a significant and lasting contribution to a modern

chemical, physical and mechanic characterisation of traditional construction

materials used in Italy, a vast theoretical and experimental research project has

been set up and systematically coordinated by nine units. These units have been

assigned particular regional materials according to the following criteria:

Bologna: Construction materials and techniques for brickwork and sandstone

walling.

Catania: Ancient construction materials and technologies typical of Sicily,

with particular reference to lava stone.

Florence 1: Construction materials and techniques typical of Tuscan historic

works, with particular attention to brickwork of various applications.

Florence 2: Construction materials and techniques typical of Tuscan historic

monuments, with particular attention to sedimentary rocks (pietra

forte and pietra serena).

Naples: Construction materials and technologies in the Campania area, with

particular regard to volcanic materials.

Potenza: Ancient construction materials and technologies of the Basilicata and

Puglia regions, with particular attention to dry stone masonry

reinforced with grey stone and Lecce tufa stone.



Rome: Construction materials and technologies of Roman archaeological

sites and monuments, with particular attention to Latium typology

and opus latericium.

Milan: Historical and experimental study of materials and technologies with

reference to durability.

Trento: Theoretical and experimental analysis of wooden material for

structural applications in buildings of historical importance, in view

of restoration work, re-use and structural adaptation.

Such a detailed and systematic research project will make a fundamental

contribution to the drafting of specific regulations for construction materials that

have been used over the centuries to build historical monuments in Italy.

The choice of tests to carry out on materials making up brickwork and

stone masonry is based on two fundamental considerations:

- The possibility of providing a classification of materials undergoing testing that

is based on their physical and mechanic properties;

- Assessment of the main physical and mechanic parameters involved in the

study of brickwork and stone work structures.

In order to set up a rigorous experimental research programme, a serious

debate was started among the units involved and a critical analysis of existing

regulations was concluded, establishing a set of tests necessary for the physical,

chemical and mechanic characterisation of the chosen materials. Methods,

optimum sample sizes, experimental equipment to be used and the quality and

quantity of measurements to be carried out were established with reference to

each test. All this was carried on with a view to a standard procedure and by

carrying out hundreds of tests. This cycle of experiments almost always used

new materials: knowledge of the properties of these materials should establish

parameters that may be used to a sufficiently reliable degree for ancient materials,

and should give a precise experimental foundation to the regulations to be

respected in static restoration work using traditional materials.

Measurement of any mechanic or physical property requires a conventional

and precise definition of the elements that are involved in the measurement

process itself. The more precise and detailed the specifications, the more

uniform and significant will be the results obtained. On the other hand, an

excessively demanding code may limit field of application of the measurement

procedure, making it difficult to extend its use to cases or materials that are either

new or somehow different from the ones prescribed originally in the regulations.



Finally, the specifications should necessarily reach a satisfactory level of

compromise between the need for accuracy in measurement and feasibility of

measurement. Use of time and financial resources must be kept within

reasonable limits, and also those interested in carrying out measurements must be

taken into account so that the required precision and test feasibility in standard

conditions may be assured.

Similar arguments were also put forward for mortars. The most suitable

components were chosen and homogeneous materials then sent to the units

concerned. Numerous sample tests were carried out and a strategy was

established in order to broaden our understanding of the properties of traditional

and local mortars.

An important novelty in all the experimental tests carried out was study of

stress and deformation of the material: i.e. the elastic parameters of various

materials were measured systematically in order to provide reliable data on many

materials to the scientific community.

At the end of the research programme, it will be possible to draw up a

classification of some of the materials used in those regions which have seen

research based on measurable parameters such as density and resistance to

compression. This classification will be a useful reference in the analysis of

brick and stone structures.

As shown earlier in the list of research units (University di Trento unit),

wooden materials have not been left out of the project. Although wood has been

used less and less in Italy over the years, it is still one of the basic components in

ancient structures and object.

These studies have hoped to attract more attention to wood as a structural

to be used especially in the preservation of historical monuments.

3 A new cultural strategy in Faculties of Engineering

The cultural strategy that has guided various Italian structural engineers in

striving towards a scientific preservation and restoration of historic monuments

according to principles already mentioned is slowly being extended to other

engineering fields. This has been the case especially in the Faculty of

Engineering at the University of Naples "Federico II", which more than any

other has been involved in thousands of projects on preservation and restoration

work carried out in Campania and Basilicata after the 1980 earthquake. This



intensive activity has led to initiatives at a national level, such as the Committee

for the preservation of seismic risks already mentioned, and the setting up of a

Committee of the National Research Council for Science and Technology of

Cultural Heritage, that has designed and funded a Strategic Project.

In this cultural light and after a long preparatory phase, an

Interdepartmental Centre of Engineering for Cultural Heritage was set up at the

University of Naples. The Centre sees the cooperation of teaching staff and

structures from different Departments: Construction Science; Engineering of

Materials and Production; Technical Physics; Electrical Engineering; Hydraulic

Engineering; Geotechnics; Construction Technology.

The aims of the centre are summarised as follows:

- To instil a critical engineering culture able to interrelate with other cultures on

historical knowledge.

- To develop a research orientation which broadens our knowledge of the "art of

construction" even in the pre-Galilean period.

- To develop research programmes promoting scientific knowledge of ancient

materials and technologies in order to apply them for a more reasoned form of

preservation that develops criteria of homogeneity, reversibility and durability.

- To specifically target the innovative contribution to technological development

to our cultural heritage.

- To contribute to the drafting of specific regulations for historic monuments

since present standards apply to modern construction methods and are not

suitable for our cultural heritage.

- To develop a series of external relations with the Ministries of Cultural

Heritage, Civil Protection and Public Works, and with peripheral agencies

such as regional authorities, commissions etc. in order to provide scientific and

interdisciplinary advice on matters.

Two years have passed since the Centre was set up and the record so far

has been positive.

The Centre has received considerable funds from the Ministry of Cultural

and Environment Heritage, the Ministry for the Universities and for Scientific

and Technological Research and the National Research Council. There are many

projects underway, in particular:

- Constant and concrete cooperation with the Centre Restoration Institute for the

drafting of the first general chapter for tenders concerning projects of



preservation and restoration work, printed by the Ministry for Cultural and

Environment Heritage.

- A research project embracing various fields, from structural to electrical,

financed by the National Research Council in order to critically revise existing

regulations in view of future applications to cultural heritage issues.

- A research programme on the engineering impact on the use, management and

protection from natural and man-made risks of archaeological sites.

4 Conclusion

We have briefly mentioned the reflections and initiatives regarding the

strategy that has been developing in Italy for engineering in general - and

structural engineering, in particular - aimed at the preservation and restoration of

historical monuments.

We cannot, unfortunately, go into greater detail here on all the research

orientations, the results obtained so far and the numerous series of interventions

carried out in a strongly interdisciplinary fashion and paying close attention to the

material history of monuments.

We hope to have contributed in some way to a wider dissemination of the

strategy outlined and we are willing to cooperate in future work in this field.

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Documents

In order to limit the damage caused by a misplaced