Restorasyon uygulamalarında kullanılan çağdaş teknikler
Contemporary techniques in architectural restoration practice
Yazar: LORY ZAKAR
Danışman: PROF. DR. KEMAL KUTGÜN EYÜPGİLLER
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Restorasyon Ana Bilim Dalı
Derece: Yüksek Lisans, 2013
Konu: Mimarlık = Architecture

Özet:
Bu çalışma, koruma ve restorasyon uygulamalarında, tarihi yapılarda gerçekleşen bozulma ve hasarlar karşısında uygulanan müdahale yöntemlerini ele almaktadır. Yaygın şekilde kullanılan çağdaş müdahale tekniklerine yer verilen çalışmada, güncelliğini kaybetmiş bazı müdahale tekniklerine de yer verilmiştir. Tezin amacı, kapsamı ve yöntemi birinci bölümde açıklanarak, çalışmanın genel hatları ortaya konmuştur.
Koruma, restorasyon, bakım, onarım, yenileme, iyileştirme, bütünleme, yeniden yapım, taşıma ve yeniden kullanım gibi konuyla ilgili temel kavramlar ikinci bölümde açıklanmıştır. Her bir kavram, yerli ve yabancı çeşitli kaynaklarda bulunan tanımların karşılaştırılmasıyla incelenmiş ve önemli noktaları vurgulanarak açıklanmıştır. Çalışmanın kapsamına dahil edilen konularla ilgili değerlendirmeler bu temel kavramlar kapsamında yapılmıştır.
Üçüncü bölümde, yapılarda, strüktür ve malzemede bozulmaya neden olan etkenler açıklanmıştır. İklimsel nedenler, biyolojik nedenler, doğal afetler ve insan kaynaklı nedenler olarak gruplanmış olan bozulma etkenlerinin dinamiklerine değinilmiştir. Bu dinamiklerin yapı malzeme, bileşen ve elemanlarına nasıl etkidiği belirtilmiştir.
Koruma ve restorasyon sürecinde uygulanan müdahale türleri, yapı elemanı ve yapı malzemesi üzerinden iki gruba ayrılarak aktarılmıştır. Yapısal sorunlar ve müdahale yöntemleri başlığıyla, dördüncü bölümde, yapı elemanlarının uğradığı bozulmalar karşısında gerçekleştirilen uygulamalar anlatılmaktadır. Temeller ve onunla ilişkili olarak zeminden başlayarak, duvarlar, taşıyıcı ayaklar, sütunlar, döşemeler, kemer, kubbe, tonoz ve çatı konularında sorunlar ve müdahale yöntemlerine değinilmiştir.
Yapı malzemesi bazında sorunlar ve müdahale yöntemlerinin aktarıldığı beşinci bölümde, taş, tuğla, kerpiç, ahşap metal, harç, sıva ve yapay taş malzemeler ele alınmaktadır. Her bir malzemenin iç yapısı ve yapıda kullanımı ile genel bilgiler verilmekte olup, malzemede bozulma etkileri altında ortaya çıkan bozulma türleri ve bu hasarlar karşısında yürütülen uygulamalar anlatılmaktadır.
Sonuç bölümünde, koruma yaklaşımlarının tarihsel süreç içerisinde evrilerek gelişmesinde etkin olan görüşler belirtilmiş ve bugün varılan nokta açıklanmıştır. Bugün restorasyon uygulamalarını yönlendiren ölçütlere değinilmiş, bunların arasından ön plana çıkan, kültürel olgunluk, teknik ve bilimsel birikim, ekonomik güç ve kaynak erişimi gibi ölçütlerin bir yapının korunması sürecine etkileri vurgulanmıştır. Bu bağlamda, teknolojik gelişimlerin şekillendirdiği uygulama tekniklerinin, çağdaş kuramsal yaklaşımları destekleyici şekilde kullanımındaki önemli noktalar tartışılmıştır.

Abstract:
Application techniques in architectural restoration, being conducted in the presence of deterioration and damage in historical buildings, are explained in this study. Ancient intervention techniques to damaged building fabric, as well as contemporary techniques are featured. The aim, extent and the method of thesis are explained in the first part, stating the main concerns of the study.
The aim of this study is to gather technical and practical information on restoration applications together for graduate students and young professionals, who begin to specialize in the field of architectural restoration. Having knowledge of traditional materials and building systems to some extent, the targeted group will be provided with information on the causes and types of deterioration of materials and structural elements along with repair techniques. Masonry materials, timber, mortars, plasters and artificial stone (non load-bearing elements) are the main focus of the study. Metal was included to the extent of decorative and  supplementary elements in masonry and timber structures. Traditional repair techniques are discussed as well as the contemporary techniques enriched by technological developments. 
Main concepts relating to the subject, such as restoration, maintenance, repair, renovation, rehabilitation, reconstruction, relocation and reuse are discussed and explained in the second part of the study. Each concept is explained, including perceptions of different national regulations. 
Third part of thesis consists of the presentation of factors playing role in structural and materialistic deterioration of historical buildings. Factors of deterioration are grouped as climatic factors, biological factors, natural disasters and man-made factors. Sunlight, air, temperature, water in the form of rain, humidity, snow and wind are the main climatic factors affecting buildings. Exposure to sunlight and air mainly cause weathering of the material. Air, including acidic gasses and tarry polutants, cause staining and the formation of gypsum crust on stones. Another climatic factor, water has severe destroying affects on materials. Water penetrates into the building fabric in form of humidity, rain or snow causing decay of materials and disintegration of structural elements. Temperature affects building fabric creating thermal stresses. And, wind usually introduces different corrosive materials to the surfaces and causes erosion by mechanical impact.
Among biological factors are animals, plants, insects, funghi and bacteria. Biological factors usually cause deterioration mainly because of their metabolic activities. They cause staining, decay, disintegration of materials. Also, because of their mechanical growth or movement potentials, they can create cracks, holes and channels into the material. 
Natural disasters such as earthquake, flood, volcanic eruption, avalanche, tsunami, etc., end up in great destructions on not only materials but also structural system of buildings. Finally, man-made factors of deterioration cover lack of maintenance, misuse, faults in design or workmanship as well as aspects like vandalism, tourism, traffic and war. 
Types of intervention conducted in conservation end restoration processes are explained through construction materials and construction elements. Fourth part, bearing the name, structural problems and techniques of intervention, consists of remedies applied to construction elements such as walls, piers, columns, floors, arcs, vaults, domes, roofs, foundations and the ground.
Alterations in ground conditions weaken the buildings, causing different settlements on the ground and resulting in deformation of foundations. Foundation elements become insufficient in terms of surface width or depth because of alterations in the ground character. Deformations, under the effect of forces caused by settleing differently, contribute to the deterioration of foundation elements. According to the specific need, the ground can be strengthened by injection or jet-grouting. Interventions regarding the foundations are usually the ones that enhance the width or depth of the surface area contacting the ground. Addition of new planks and micro-pinning are main techniques for the amelioration of foundations.
Walls, in either masonry or timber construction, exhibit many different forms of deterioration and deformation. Masonry walls can be cleaned with many mechanical and chemical techniques. Along with stitching and injection techniques, materials like tie-rods, fiber reinforced polymere (FRP) rods or textiles are used for consolidation and strengthening of masonry walls. Different masonry materials such as stone, brick and adobe are taken into consideration while discussing the repair techniques. Along with those techniques, partial or complete reconstruction of a constructional element can be necessary. Timber construction walls are usually repaired by partial or complete reconstruction of decayed elements.
Wall consolidation and strengthening techniques are similar for arches, vaults, domes and pillars. Walls, arches, vaults, domes, pillars and columns exhibit different performances under certain structural forces beause of their unique geometry. Thus, many techniques are basically the same for these masonry structural elements but they are modified for each of them. Tie rods and reinforced polymere elements are applied in specific positions, on specific parts of the elements that need support against tension forces. Although it is an old and traditional technique, arches, vaults and domes can still be strengthened by buttresses against deformations. Metal rods can be applied on tension-bearing surfaces of arches. Columns, usually made up of monolithic pieces without mortars, can be strengthened by metal strapping. Thus, the repair techniques for structural elements are explained regarding construction with different materials.
Floor and roof constructions are both discussed in two parts. Floors are grouped as masonry and timber floors, where roofs are grouped as flat roofs and pitched roofs. Masonry floors are usually made up of metal girders and masonry vaults. Girders are lined up paralel to each other and the void between girders are filled in with vaults usually made up of brick. Timber floors, on the other hand, are made up of timber beams carrying planks and coverings. In both floor types, deterioration and repair occurs on both the load bearing and covering layers.
Similarly, roofs are constituted by load bearing and finishing parties. Flat roofs require constant maintanence for their earthen finishing layers supported by timber beams. Insulation layers can be added to the earthen finishings for strengthening flat roofs against climatic factors of deterioration. Pitched roof consolidation can be realized with many techniques such as, implementation of metal rods, cables, fiber reinforced polymere rods or textiles, partial or complete renewal of load bearing elements and addition of a new element. 
In the fifth part, problems and interventions on construction materials such as stone, brick, adobe, wood, metal, mortar, plaster and artificial stone are being explained. General information on the inner structure, properties and its constructional use is provided for each material. Under the effect of deterioration factors, types of deterioration undergone and varieties of possible interventions are explained.
For each material have different inner structure, physical and chemical properties, the deterioration mechanisms also differ. Cleaning, repair and application of protective coatings are the main steps of interventions to deteriorated materials. Decay, staining, deterioration under metabolic activities of biological agents, break down caused by wet-dry, freeze-thaw cycles are main types of deterioration observed on stone. It is possible to use many techniques to clean stone surfaces. Cleaning with water, laser cleaning, cleaning with blasting, chemical cleaning, biological cleaning are techniques available to remove dirt, stain, gypsum crust, etc. from stone. In case of euflorescence, the salt formations can be removed using special putties. Repair on stone is done on the surface using consolidants or inside the material, using special glues and fixing rods, if any parties are lost. Final step of intervention is usually the application of protective coatings like, biocides, water repellent chemicals and special coatings like self-cleaning nano coatings or biocalcification.
Brick is a very durable material. Manufactured under high temperature and pressure, it exhibits a homogenious inner structure. Water, salt crystallization, fire, faults in manufacturing process are basic effects of deterioration of bricks. Cleaning, repair and strengthening for bricks is similar to applications on stone. Another masonry material, adobe is mostly deteriorated by water. Since the main component of adobe is earth, water causes serious disintegration and deformation of the material. Repair and consolidation of an adobe block might not be very efficient or feasible in many cases. Renewal with the same material or the use of a strengthened material with additives are possible in adobe restoration practice. 
Wood is an organic material that deteriorates as a result of exposure to air, sun light and water/humidity. Biological factors like funghi and insectes are also very destructive on wood material. Mechanical or chemical cleaning, consolidation and protection by impregnation and fumigation are common methods of intervention. Decayed parts are usually renewed with new wood. Similarly, to repair deteriorated metal, partial or complete renewal is often needed. Chemical or galvanic corrosion results in material loss of metals. Errosion, excessive loading, faults in design or workmanship are others effects causing metal deterioration. The consolidation and protection interventions are mechanical or chemical cleaning followed by chemical applications to consolidate and protect the material. Painting the metal is essential both for consolidation and protection. Injections, addition of plates, straps or stitches are common repair techniques. Besides paints, water repellents and anti-corrosion coatings can be used as additional protective layers. 
Mortars and plasters decompose under atmospheric effects and biological formations. Loosing the ability to bind, plasters stake fall and exhibit deformations. They are cleaned mechanically or chemically. Injection, renewal with repair mortars or plaster and stregthening with metal rods are possible techniques of intervention. Finally, artificial stone elements spesifically used as façade ornaments and surface claddings exhibit black crust formation, staining, cracking and falling off. They are also cleaned by mechanical and chemical means. Injection, repair of micro cracks, reattachement to the bearing surface and renewal with a new piece are the most common techniques of intevention. 
Having discussed main aspects of restoration practices in terms of constructional elements and materials, it can be seen that technology is leaking in and transforming the field of architectural restoration. Since the importance of original fabric of an old building gets the ultimate priority in modern conservation philosphy, newly implemented materials and techniques of intervention have critical importance. Lots of questions regarding the original fabric come up in the actual construction process: How the old will work with the new, how flexible and revertible can the inplementations be, how can we elongate the lifetime of old materials without making them loose their authenticity. The challenge of the era to answer these questions is still valid. Technological developments are inevitable and they also provide the field of conservation with lots of new possibilities including nanotechnology and biotechnology. Understanding the importance of the existing old building fabric, using technology for its benefit and always planning ahead is and will be the key to future restoration practice.