METHODOLOGY_FOR_THE_RESTORATION_OF_HERITAGE_PROPERTIES.pdf

Studies, methodologies and diagnosis for the conservation and restoration of cultural heritage

1. 9
th
INTERNATIONAL (CICOP) CONGRESS ON ARCHITECTURAL HERITAGE
REHABILITATION AND BUILDING SEVILLE 2008




METHODOLOGY FOR THE RESTORATION OF
HERITAGE PROPERTIES

A. Čaušević MSc.
(1)
, N. Rustempašić MSc.
(2)

Faculty of Architecture of the University of Sarajevo

[email protected]
(1)
, [email protected]
(2)


THEMATIC AREA: Studies, methodologies and diagnosis for the
conservation and restoration of cultural heritage.


ABSTRACT

Successful realisation of any task assigned, including the reconstruction of damaged, or neglected
buildings, requires methodical approach. If we are considering buildings of cultural-historical
heritage, methodology of their reconstruction is set in more strict form than the one of ordinary
buildings. Confirmation of this statement could be found within the legal regulations which,
underlying the importance of cultural-historical heritage, specifically define what kinds of objects
these are.
A number of specialists of specific professions should participate in the process of reconstruction,
especially important being the following ones: investor, beneficiary, architects and town planners,
civil construction engineers of different specialties, particularly specialists in the fields of structuring,
soil mechanics, geodesist, geologists, conservators and restaurateurs, archaeologists and art
historians.
This paper gives a framework methodological approach for realisation of reconstruction of buildings
(or ensembles) of cultural-historical heritage. Furthermore, the paper gives orientation cell-chart of
the order of above described activities – the levels of detection and diagnostics of object damages.
Starting from the assumption that a valid detection has been preformed, including the set definition
of the causes of object damages, and considering buildings' function(s), it is possible to make a
decision on measures to be taken in order to restore building's functions, or in other words on their
future status. With this purpose a cell-chart will be given, outlining a number of actions to be
undertaken within repair work and reinforcement of the damaged buildings.

Key words: Methodology, project documentation, research, survey, detection and diagnosis.

1. MULTIDISCIPLINARY APPROACH

The restoration of heritage properties is dictated by need, use, and available resources. Several
people with a range of specializations must be involved, in particular: The investor or
occupant/beneficiary, Architects and town planners, Civil engineers from various specialist
backgrounds, primarily construction and geomechanics, Surveyors, Geologists, Conservers and
restorers, Archaeologists and Art historians.
Each of these will have his or her own view of the solution, particularly as regards the priorities,
extent and order of the necessary works.
The investor’s aim is to achieve the desired objective at minimum cost, particularly when there is to
be a change of use from the original use of the property, for example into a catering establishment,
so as to recover the investment as quickly as possible and to make a profit thereafter.
The architect indubitably plays the leading role, particularly if also acting as project design and
implementation coordinator. This means that he or she will be expected to have extensive and
comprehensive knowledge of the wide range of problems involved, and will bear the greatest
responsibility.
The role of civil engineers is also significant, since they will be expected to determine the precise

2. 9
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INTERNATIONAL (CICOP) CONGRESS ON ARCHITECTURAL HERITAGE
REHABILITATION AND BUILDING SEVILLE 2008



condition of the load-bearing structure and to suggest the possibility and modalities of new
interventions.
Specialists in geomechanics need not only to diagnose the causes of damage to the properties
arising from subsidence or the insufficient bearing capacity of the foundations, but also to decide to
what extent further loads can be added or the existing foundations be reinforced.
Surveyors are essential in order to make an accurate survey of the site of the building and its
various elements; they play an especially important part in determining the exact deviation from the
vertical, if any, of walls and pillars, and in monitoring how accurately the works are being executed.
Geologists are required to identify the composition of the soil beneath and around the building and
the presence or absence of subterranean waters, as well as their impact on the site in question as a
whole.
By the nature of their work, conservers and restorers are involved as required once a detailed
project has been drawn up. Art historians must also be involved in defining the project, since the
artistic valorization of the building or ensemble depends on their professional opinion.

2. METHODOLOGICAL FRAMEWORK

There follows a framework methodological approach to the implementation of restoration works on
heritage properties or groups, which will be developed in greater detail at a later stage.

Table 1. FRAMEWORK METHODOLOGY FOR RESTORATION

1. INVESTOR/MANAGER OF THE PROPERTY- PROJECT TASK
2. DRAW UP PROJECT DOCUMENTATION (SELECTED DESIGN COMPANY)
3. REVIEW

4. SELECTION OF CONTRACTOR – GUARANTEE

5. IMPLEMENTATION

6. SUPERVISION
INVESTOR PROJECT DESIGNER
7. TECHNICAL INSPECTION OF COMPLETED WORKS

Table 2. ANALOGY HEALTH AND STRUCTURE
HEALTH STRUCTURE
prevention properly designed project
pathology structural damage
examination and diagnosis detection and diagnosis

CURE:

ELIMINATION:
conservative, repair
radical/aggressive, reconstruction
none/no treatment demolition

3. DEVELOPMENT OF OUTLINE PLAN

The Investor is responsible, in line with his needs, intentions and economic capacity, for drawing
up a clear project task with a precise definition of the future use of the building to be restored.The
investor is also responsible, within the context of the duly defined project task, for determining the
cultural and historical valorization of the building – the UNESCO categorization – in a qualified and

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INTERNATIONAL (CICOP) CONGRESS ON ARCHITECTURAL HERITAGE
REHABILITATION AND BUILDING SEVILLE 2008



professional manner, in consultation with relevant authorities and institutions and in line with the
provisions of the law and conventions, since the categorization sets constraints on all works that
may be carried out and prescribes the types and quality of the materials that may be used.
There are cases in the categorization of properties to which extremely strict measures must be
applied as regards the options, methods and use of materials, so as to exclude any possibility of
alteration to the original forms, bearing structures and building materials.

4. PROJECT DOCUMENTATION

Along with implementation, this is the fundamental and most complex task to do with the restoration
of such properties. Compiling the project documentation entails a range of activities that underpin
the concept on which it is based.

Research or preparatory activities form the starting point of this range of activities, the most
important of which include:

- Bibliographical research, an indispensable component of the preparatory activities, providing the
project designer(s) with the initial data that enables them to create as true a picture as possible of
the building or group and, if possible the historical background of the property up to the present day.

- Observation of the current condition of the building and its surroundings. Several separate
observations must be carried out jointly with all major participants in the compilation of the project
documentation and with each individual team member.

The purpose of preliminary observations is to arrive at an overall view of the current
condition of the building, and to conduct a joint analysis of its defects and the potential for
making adjustments to the project solution. As has been demonstrated in practice, this first
impression may also be the final impression, and hence any omissions or oversights will have an
adverse impact on the completion of the task.

It must therefore be comprehensive and thorough e.g. it must cover the following areas:

• Regardless of whether there are any earlier drawings of the building, a detailed survey of the
entire building is essential, along with its immediate surroundings. These geometric data must
be very accurate, to avoid the need for additional surveys at a later date. The surveys should
record and describe not only the details of the site but also all damage observed, deviations,
sagging of the interstorey structures etc.
• As a rule, this requires not only the removal of the outer cladding or even of parts of a wall to
determine the depth of cracks but also, if there is any suggestion of subsidence, exacavations
around the building or to the depth of the foundations.
• The bearing structures of the building must also be accurately identified.
• Even at this early stage of investigative works it may prove necessary to secure certain
structural elements, or even the entire building, to prevent it from collapsing.
• The elements that need reinforcement or conservation can be identified during the initial visit,
and provision can immediately be made to take the necessary steps to relieve the load.
• It is very important at this early stage of observation of the building to determine the type of
binders (mortar) used in the masonry structures, together with other connecting devices.

It should be obvious that all this must be carried out with the greatest care, accurately and
systematically, since the data, and any works carried out at this stage, form the basis for drawing up
the project documentation. Once all relevant data have been collected, work may begin on
designing a renovation project, which must conform to all current standards for the drafting of
project documentation.Though it may at first glance appear to be unnecessary or insufficiently
accurate, the preliminary level is in fact the most important.

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INTERNATIONAL (CICOP) CONGRESS ON ARCHITECTURAL HERITAGE
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The basic activities at this level are:

1. A review of the original project documentation, if available in order to gain familiarity with the
building as a whole – which is not contrary to the notion of revision noted above.
2. A detailed visit of the building and its immediate surroundings so as to:
• determine whether the building was built in line with the project documentation
• determine whether any later interventions have been carried out
• it is particularly important, when viewing the building, to make an accurate identification of
the bearing construction and of the type of materials used to build it,
• the above operations naturally include listing all damage, whether observed or indicated,
particularly to the bearing structural elements, and to record them on appropriate drawings,
• determine whether the building as a whole, or parts thereof, are stable, which is a
prerequisite for reaching a final decision on how to eliminate the damage and the options
for carrying out the works, as well as on its future status generally,
• determine whether there is any visible damage to the service installations.

In order to achieve these objectives, and given that the observations and recordings serve as the
basis for the project to repair, reinforce or reconstruct the building, a proper record of each visit
should be maintained in writing, accompanied by appropriate drawings and noting the nature,
extent and position of all instances of damage.The diversity and atypicality of the work of recording
all visible and latent damage calls for multiple checks and accurate descriptions on the
corresponding drawings.The most sensitive issue, without doubt, is determining the condition of the
foundations. With the general opinion of the building’s stability in mind, this should be addressed
with the utmost care. Since the foundations are a crucial part of the building, it is vital to consult a
specialist in geotechnics and foundations, particularly if there are signs that the foundations are
damaged. These signs could consist of major cracks in the basement walls, particular at the
corners, depressions or cracks in the soil beside the building, displacement of pier bearings, and
such like.On completion of all these operations, the expert group either adopts an internal resolution
on the need for further detection and diagnosis, or agrees that these preliminary findings are
sufficient.If the latter, work can proceed on drafting the project documentation for the elimination of
the damage.

This documentation should, as a rule, include:

• all the necessary drawings and plans of the condition of the building as found, with the position
of each instance of damage marked and specified by type, along with a written description,
• the manner and methodology by which the damage will be eliminated
• a bill of quantities and cost estimate of the works to be carried out,

If thought necessary, the report should include a description and drawings of the measures to be
taken to prevent loose material from falling, and of the manner in which the load is to be relieved on
bearing elements being reinforced, removed or replaced.The first visit may be regarded as a
preliminary survey, the primary level of detection, since it is very common for further inspections
to be required, which also take one to a higher or secondary level, intended to obtain additional
relevant information. This in itself means widening the range of specialists, as well as obtaining
further information on the building materials used and the soil on which the building stands.Then
again, as will become clear, the preliminary level may be regarded as the basis for conducting the
next, secondary and tertiary investigations, if it should prove necessary.Common to both levels are
additional detection and expert diagnosis of major damage.When seeking an appropriate response,
as well as taking account of modern views on the design of seismic-resistant buildings, which
programmes in yield points (non-elastic behaviour of certain elements at selected points), it is
essential to identify the cause of the problems that have emerged, always supposing the project to
have been properly designed.This is the reason for raising diagnosis to a higher level, all the more
so since the preliminary level is clearly insufficiently comprehensive to provide all relevant
information, including the most sensitive. If it should prove necessary, additional data collection is

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INTERNATIONAL (CICOP) CONGRESS ON ARCHITECTURAL HERITAGE
REHABILITATION AND BUILDING SEVILLE 2008



undertaken, primarily relating to the laboratory testing of materials, and samples of basic
materials are taken, including tests in situ, suggesting in practice that the process has moved onto
the secondary level.Secondary diagnosis is more challenging than preliminary diagnosis, since it is
based principally on accurately identifying the characteristics of the building materials and checking
the quality of execution, particularly details of joints and connections.

This type of diagnosis is particularly necessary in the following cases:

• large, wide cracks in the masonry, extending into the basic building material (e.g. brick),
• deviations from the vertical in the case of walls, pillars, piers etc.

All these and similar features suggest the need to take samples and conduct laboratory tests.Only
once all these activities have been completed, including particularly all laboratory tests, can a
proper judgment be formed of the causes of major damage, and thereby of the way to eliminate it.
This is the place to draw attention to another serious problem that often accompanies major seismic
action – the outbreak of fire.
It should be noted here that in some special cases, where particularly valuable properties are
concerned, the secondary level too may prove inadequate, resulting in the need for the highest or
tertiary level of detection, which naturally increases the costs of the entire process of detection on
which the working project will be based. If all the activities listed above fail to produce satisfactory
answers, the diagnostic process is raised to a higher level.
It should be said right away that the tertiary level is required only in exceptional cases of damage
to outstanding buildings of which the stability has been undermined or which are sinking, as well as
where there is serial major damage to a number of buildings on the same site. In addition to
entailing the completion of the procedure of the previous two levels, additional monitoring and
testing using sensitive apparatus is required, with the use of ultrasound and scanning of the places
marked as of particular importance in identifying the cause(s) of the damage. Moving to the tertiary
level is based on two assumptions: that the project documentation has been properly drawn up and
that all activities pertaining to the first two levels have been completed without providing satisfactory
answers.The procedures required at this level are so demanding that they can be carried out only
by highly-qualified specialist institutions and individuals, making them very expensive to conduct. As
will be seen, the procedure is in fact a scientific study, the purpose of which is primarily to identify
with certainty the causes of collapse or major damage and thereby to determine whether and how
the damage can be eliminated and the building reinforced, but also to serve as an expert
contribution to potential corrections in the process of designing aseismic structures.The starting-
point for the tertiary level of diagnosis is the view that the initial data for the project design were
flawed, particularly as regards the key parameter – the maximum projected soil acceleration. To
corroborate or negate this view, all significant data on the earthquake on the site that had a serious
impact on the building under consideration need to be collected.To this end, the site of the
epicentre is studied, along with the actual magnitude, seismoscopic records of the soil, the details
of the accelerograms from which the predominent periods of soil vibration are extracted, possible
acceleration amplifications from bedrock to surface, etc.In practice, a detailed dynamic analysis of
the responses of the building is conducted in which a step-by-step system of the strong section of
the accelerogram is used to track events in the building such as rigidity degradation, changes in the
dissipation of internal energy, the opening of plastic joints or the discovery of plasticized zones in
general, the redistribution of loads, and numerous other relevant indicators. Interactions are taken
into account, naturally: building-foundations, and building(with foundations)-soil.
Only on the basis of such analysis is it possible to obtain reliable answers to the question of the
causes of unfavourable responses and carry out the appropriate corrections.The next step is to
draw up appropriate documentation in the form of a study or project to eliminate the damage,
depending on the type and extent of the damage that is to be identified and the conclusions that this
leads to. The insistence on accurate detection and diagnosis of the damage is justified in the light of
the fact that there are almost always hidden damage points, usually revealed only after opening up,
i.e. after the start of works. To reduce unforeseen circumstances to a minimum, a special
methodology has been evolved in some countries, adjusted to various incident situations and

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INTERNATIONAL (CICOP) CONGRESS ON ARCHITECTURAL HERITAGE
REHABILITATION AND BUILDING SEVILLE 2008



comprising forms or questionnaires for various types, to be accompanied by the requisite comments
from the expert group.
CELL-CHART 1. organization chart of the activities described above – the levels of detection
and diagnosis of damage to buildings.
REQUEST FOR A SURVEY AND DIAGNOSIS OF THE CONDITION OF THE BUILDING

PRELIMINARY DETECTION

STRUCTURAL SYSTEMS FINAL WORKS INSTALLATIONS,FIXTURES etc.

PRELIMINARY DIAGNOSIS

DECISION ON LEVEL OF DIAGNOSIS

MAIN DIAGNOSIS

STUDIES OF THE SITE

SEISMIC DIAGNOSIS:


DIAGNOSIS BY
DYNAMIC A
NALYSIS OF
STRUCTURAL
SYSTEM
DYNAMIC ANALYSIS:
(construction+, final works ,
installations,fixtures etc. )
-characteristics of
earthquake
- PRIMARY - simulation of possible
earthquake on the site
- SECONDARY - elastoplastic analysis of
response
- TERTIARY

ASSESSMENT OF RESISTANCE OF THE BUILDING

PROJECT TO REINFORCE THE BUILDING

EXECUTION

5. CONCLUSIONS

Cultural monuments are immovable and movable objects and groups of objects of
importance for society on account of their archaeological, historical, sociological,
ethnographic, artistic, architectural, urbanistic, technical or other scientific or cultural
values. The restoration of such properties is dictated by need, use, and available resources.
Coordination is therefore vital, requiring a team leader. Given the nature of the problem and the
need for the widest possible overview of all the needs and requirements involved, the team leader
should be an architect, and must be able to make independent decisions.
Depending on the cause and extent of the damages, process of detection and diagnosis is
implemented at three levels: preliminary and secondary, as well as tertiary in exceptional cases.
The entire process of drafting a study on renovation or restoration is not complete, of course, until
the causes of the building’s deterioration have been identified. It is essential that these
possible causes be carefully identified and analyzed in order to avoid, or prevent, a
repetition of the mistakes that led to the present condition of the building. The repair and
strengthening of historical monuments should be carried out without introducing any
changes or strengthening of the main structural systems.