-
4-5
2014
4 5 DECEMBER 2014
FIRST SCIENTIFIC - APPLIED CONFERENCE WITH INTERNATIONAL PARTICIPATION
"PROJECT MANAGEMENT IN CONSTRUCTION"/PMC/
UNIVERSITY OF ARCHITECTURE, CIVIL ENGINEERING AND GEODESY
PROJECT FOR PROCESS OF EVALUATION, RECOGNITION AND
SELECTION OF METHODS FOR PRESERVATION OF
HISTORICAL AND CULTURAL HERITAGE
F. Rangelova148, E. Abdulahad149, J. Cenkova150,
Keywords: project, evaluation, methods for preservation of cultural heritage
Research area: management of historical and cultural heritage
ABSTRACT
Preservation of historical and cultural heritage depends on the evaluation, recognition
and experience of the professionals and the planning, procedure and methods that they
choose. The original design, configuration, materials, character defining elements, and as
well as the technique or techniques of construction originally utilized to bind them together
should be respected, protected and preserved. Regardless of its physical dimensions, the
excellence of historical and cultural heritage depends entirely on its meaning and importance.
Recognition of the values and significance of the historic and cultural structures dictates the
fundamentals of the planning and the procedure of the preservation. This paper presents
preparation for an experimental project for evaluation, recognition and selection of methods
for preservation of historical and cultural heritage.
1. Introduction
Bulgaria is a crossroads and a cradle of ancient civilizations. It is a country of
immense Historic and Cultural Heritage (HCH) accumulated during many epochs and
148
F.Rangelova, Assoc. Prof. Dr. Eng., UACG, Department of Construction management and
Economics, Faculty of Structural Engineering, Corpus B, floor 10, study 1038,
fantina_frp@abv.bg
2
FCE,
e-mail: georgosing@gmail.com
150
J. Cenkova, PhD student, UACG, Department of Construction management and
Economics, Faculty of Structural Engineering, Corpus B, floor 10, study 1039, e-mail:
jolina_cenkova@abv.bg
446
civilizations
pre-historic, ancient Thracian, ancient Greek, Roman Byzantine, ancient
Bulgarian Islamic and the Bulgarian national revival. All this warrants our history and its
heritage to be considered as one of the most important feature of the image of our country.
Bulgaria has preserved 179 cloisters and 3911 churches, among them Bojana church,
Alexander Nevsky Temple monument, Rila, Batchkovski, Rojenski and others monasteries
are of world renown.[1,2]
Many ancient settlements of all civilizations on Bulgarian soil are also preserved:
Stara Zagora (8 000 years), Apolonia (Sozopol), Mesemvria (Neseber), Nikopolis ad Istrum,
the Old Bulgarian capitals Pliska, Preslav and Veliko Turnovo.[3]
At present there are not enough effective instruments for the conservation. The
construction activity in some cultural and historical centres causes problems with respect to
their look and authenticity.
The most sensitive aspect of the rehabilitation of existing buildings is their structural
rehabilitation. The eventual strengthening of existing buildings of HCH can conflict with
their cultural value. Therefore, the type of intervention on the heritage building will depend
on the existing situation of the building, and also, on its cultural value, going from simple
maintenance, where the objective is not to change the cultural value of the building, to deep
rehabilitation, when it is intended to improve the constructive performance of the building.
The actuality of the problem of strengthening and rehabilitation of the buildings of
HCH give to us reason to prepare one experimental work at the UACG for evaluating the
strengthening techniques of masonry arch structures with application of the traditional and
advanced FRP materials and systems.
2. Define the necessity of preservation of historical and cultural
heritage
Heritage buildings are defined as existing buildings with significant cultural value to
society. The cultural value of an existing building is as high as it is old. Rehabilitation of
heritage buildings has become an issue of great importance around the world. It is the result
of the need to improve existing buildings for new conditions of sustainable development of
Word, and also of the recognition of the importance of conservation of the architectural
heritage.
The need for structural rehabilitation of heritage buildings is, usually, motivated by
one or more of the following reasons:
The visible defects in the building;
Damages after natural disasters and accidents;
The change of the use of the building for most severe conditions; and
The need to be in accordance of the Requirement of regulations for
construction (Euro codes).
A basic point in considering structural rehabilitation of a heritage building is
establishing the performance level to be fulfilled, particularly, the requirements in terms of
structural safety and the level of the structural safety.
o
o
o
o
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3. Evaluation of the construction of the historical and cultural
heritage
For any purpose for structural rehabilitation and strengthening of the heritage
buildings need to have information about its past, namely, about the concept of the building,
as well as about the phenomena to which the building has been subjected. This survey,
covering the whole life of the building, aims at understanding the concept of the building, the
techniques that was used in its construction, the materials that were applied, and the
environment. One of the very important works is to understand the events that provoke
damage to the building structure, as especially seismic activities of the region. The history of
the building has to be known.
The construction of the building, including its elements, the types of structural
system, is aspects that will need considerable attention. This information will be obtained
from the documents of the building (if there are), or from the inspections on the site.
The preliminary inspection of the existing building will give the information about the
problems. The survey will be carried out through visual inspection. The results of the
preliminary inspection will be given the information for the materials and their degradations
and for the damages to the structural elements. The observed defects and problems in the
building structure will be classified qualitatively, according to their level of importance with
respect to the safety of the building.
In the preliminary inspection it will also be important to verify if the atmospheric
agents are degrading the building in a particular way. In fact, those effects are often
aggravated if adequate measures have not been taken during construction (adequate drainage,
for example), or, if there has not been efficient conservation of the building.
One of the most important inspections is on the foundation of the HCH building.
Preliminary inspection results and the data from the building documents will
determinate eventually the needs for implementation of detailed investigation of the HCH
building structure. The decision about the type and way of the strengthening and
rehabilitation will be decide after collection of all needed data, and with respect of the
specific characteristics and conditions of the HCH building.
4. Recognition of criteria for preservation of historical and cultural
heritage
Heritage buildings, by their very nature and history (material and assembly), present
challenges in diagnosis, analysis and rehabilitation, which limits the application of modern
legal codes and building standards. Furthermore, the structural rehabilitation of heritage
buildings has implications of architectural, structural, economic, historic and social order,
depending on the degree and extension of the intervention. All these aspects will be taken
into consideration. The intervention for structural rehabilitation will involve the application
of technical knowledge, and also, cultural sensitivity. Only when technique and culture is
present, can the best decisions about the intervention are taken. [6]
To succeed well, from the technical and the cultural points of view, intervention will
be carried out on the basis of principles. The Venice Chart (1964), which is one of the
reference documents for the rehabilitation of architectural heritage, defends the adoption of
the following principles:
448
o
o
o
o
o
o
o
Respect for the cultural value of the building;
Compatibility of the materials;
Minimum intervention;
Reversibility of the intervention;
Guarantee of structural safety;
Integration on the whole building;
Minimum cost.
It is not always possible to follow all these principles at the same time, but have to
find the most appropriate one for the every specific case.
Regarding to the inspection data the rehabilitation could be Preservation,
Rehabilitation, Restoration, or a combination of these actions or processes. Once the primary
treatment type is established, it is important to refer consistently to the standards related to
that treatment type for the overall project. If a different treatment is required for certain
character-defining elements, then the related standards will guide interventions on those
elements.
The Preservation: The Preservation involves protecting, maintaining and stabilizing
the existing form, material and integrity of an HCH buildings or individual component, while
protecting its heritage value. Preservation can include both short-term and interim measures
to protect or stabilize the place, as well as long-term actions to stave off deterioration or
prevent damage. This will keep the building serviceable through routine maintenance and
small repairs, rather than inoperable during intrusive interventions, extensive replacement
and new construction. Consider Preservation as the primary treatment when:
o
o
o
Materials, features and spaces of the historic place are essentially intact and
convey the historic significance, without extensive repair or replacement;
Depiction during a particular period in its history is not appropriate; and,
Continuation or new use does not require extensive alterations or additions.
The Preservation tends to be the most cautious of the conservation treatments and
retains the most materials. It is therefore more appropriate when heritage values related to
physical materials dominate. A plan for Preservation should be developed before work is
undertaken.
The Rehabilitation. The Rehabilitation involves the sensitive adaptation of an HCH
building or individual component for a continuing or compatible contemporary use, while
protecting its heritage value. Rehabilitation can include replacing missing historic features.
The replacement may be an accurate replica of the missing feature or it may be a new design
compatible with the style, era and character of the HCH building elements. Consider
Rehabilitation as the primary treatment when:
o
o
o
Repair or replacement of deteriorated features is necessary;
Alterations or additions to the historic place are planned for a new or
continued use; and,
Depiction during a particular period in its history is not appropriate.
The Rehabilitation can revitalize historical relationships and settings and is therefore
more appropriate when heritage values related to the context of the HCH building dominate.
A plan for Rehabilitation should be developed before work begins.
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The Restoration. The Restoration involves accurately revealing, recovering or
representing the state of an HCH building or individual component as it appeared at a
particular period in its history, while protecting its heritage value. The Restoration may
include removing non character-defining features from other periods in its history and
recreating missing features from the restoration period. The Restoration must be based on
clear evidence and detailed knowledge of the earlier forms and materials being recovered.
The Restoration is considering as the primary treatment when:
o
o
o
significantly outweighs the potential loss of existing, non character-defining
materials, features and spaces from other periods;
Substantial physical and documentary or oral evidence exists to accurately
carry out the work; and,
Contemporary additions or alterations and are not planned.
The Restoration is most appropriate when strong associative or symbolic values have been
obscured and can be revealed through removals, repairs and replacements based on historical
evidence. Before the work begins, the Restoration period must be selected and justified and a
plan for Restoration developed. The use of traditional methods and techniques should be
encouraged, where possible, in a restoration project. Restoration is rarely used as the primary
treatment for an entire historic place, but rather as a secondary treatment for specific
character-defining elements. If changes to an historic place have acquired value over time,
then Preservation or a combination of Preservation and Rehabilitation would be more
appropriate.
5. Selection of methods for preservation of historical and cultural
heritage
The intervention for structural rehabilitation of heritage buildings comprises, in
general, the following phases/actions [6]:
1)
2)
3)
4)
5)
6)
Acquisition of documented data about the building;
Detailed survey of the existing condition of the building;
Elaboration of the diagnosis (eventually, with the carrying of tests);
Assessment of the structural safety;
Design of the solutions for the intervention;
Execution of the intervention.
A detailed description of these phases or actions will be presented on the following
sections. Depending on the actual conditions of the HCH building and on the objectives to be
fulfilled, the intervention can assume different forms, going from the non invasive (with the
imposition or not of restrictions of use), passing through different kinds of works of repair
and/or strengthening, until, eventually, partial demolition followed by reconstruction [6].
Cost-benefit analysis have to be done when decide about the solutions of the
strengthening and rehabilitation work. One of the most important points of view remains the
compatibility of the structural safety with respect to the cultural value of the building, and
the cost to be as low as possible.
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The design of the work for the structural rehabilitation of HCH buildings can be
developed in phases, as for new buildings (preliminary design, execution design, etc), but, in
general, it will be developed in a single phase, after, and as consequence of, the structural
assessment that has been carried out on the building.
The works proposed for the strengthening and rehabilitation should be accompanied
by detailed specifications for their execution, namely about the materials to be used and their
conditions of application, the phases of execution, and the equipment necessary. An estimate
of the cost of each work, established in a realistic way, should also be included.
The huge research effort carried out around the world, during the last decade, with the
purpose of evaluating the performance of solutions for the repair and/or strengthening of
structures, in particular of heritage buildings, should not be overlooked. As a result, there are,
nowadays, multiple solutions that have proved to be efficient for the repair or the
strengthening of heritage buildings, depending on the defects to be corrected [6].
In the following clauses, the most common solutions for the repair of building
materials and for the strengthening of building elements are presented, as well as solutions
for upgrading foundations and for the improvement of safety against earthquakes of heritage
buildings.
6. Experimental work
The experimental work that will be implemented in the UACG laboratory aims to
explore conventional and advanced methods of strengthening and rehabilitation of masonry
and reinforced concrete arch elements. This type of structural elements, usually masonry,
often present in the configuration of the buildings of HCH.
The shape of the test specimens is given bellow:
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The advanced strengthening and rehabilitation solution will be implemented with
7. Conclusions and future work
Heritage buildings are defined as existing buildings with significant cultural value to
society. The intervention for structural rehabilitation will involve the application of technical
knowledge, and also, cultural sensitivity. Only when technique and culture is present, can the
best decisions about the intervention are taken.
The actuality of the problem of strengthening and rehabilitation of the buildings of
HCH give to us reason to prepare one experimental work at the UACG for evaluating the
strengthening techniques of masonry arch structures with application of the traditional and
452
advanced FRP materials and systems. Comparison between the two methods will be made
and will be given recommendations.
LITERATURE
1. Konstantinova, A. Bulgarian Cultural (and Architectural) Heritage
on Crossroads.
Architecture, XLI, 1994, No 3, p.p. 32-33 (in Bulgarian).
2. Krastev, T. Strategy of Protection of the Cultural Heritage in the Transition Period the
Case of Bulgaria. Architecture, XLIII, 1996, No4, p.p. 9-10 (in Bulgarian).
3. Vatkov, P., P. Petrov. The Cultural and Historical Heritage (of Bulgaria) from Statics to
Dynamics, from past to future. Architecture, XLIII, 1996, No4, p.p. 11-13 (in Bulgarian).
4. Tepavitcharov D.T. Problems of the Bulgarian Cultural and Historical Heritage (CHH) in
the Context of the Regional Development
5. Minkov, I. Architectural and Historical Reservation of Bulgaria Present and Future.
Bulgarian Folklore, XX, 1994, No4, p.p. 102-106 (in Bulgarian).
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Structural Assessments and Redesign of Masonry Wall Structures, CIB
150, 1992
7. RILEM, Test for masonry materials and structures, RILEM TC 127-MS, Materials and
Structures, 29 (459-475), 1996
8.
Building in Lisbon
9. ISO, Bases for Design of Structures: Assessment of Existing Structures, ISO/DIS 13822,
2000
10.
rogress in
Structural Engineering and Materials, 4 (3) (301-319), 2002
11. ICOMOS, Recommendations for the Analysis, Conservation and Structural Restoration
of Architectural Heritage, ISCARSAH, ICOMOS, 2003
12. SIKA, Sika CarboDur FRP Composites for Repair and Strengthening of Structures, Sika,
2003
th
13.
Meeting of
Commission CIB W023, Padova, Italy, 2003 (in CD-ROM)
14. EUROCODE 8, Design of Structures for Earthquake Resistance, Part 1: General Rules,
Seismic Actions and Rules for Buildings, EN 1998-1, CEN, 2004
15.
-284), 2004
16. EUROCODE 6, Design of Masonry Structures, Part 1-1: General Rules for Reinforced
and Unreinforced Masonry Structures, EN 1996-1.1, CEN, 2005
17.
Structures, Cairo, Egypt, 2006
-Masonry
18.
New Delhi, India, 2006
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