Papers A Sustainable View to ‐ Balat District

Kishali E. Politecnico di Milano, Building Environment Science Technology (BEST) [email protected] Grecchi M. Politecnico di Milano, Building Environment Science Technology (BEST) [email protected]

TRADITIONAL TECHNIQUES AND DISTRICT REHABILITATION

Sustainable rehabilitation and preservation strategies in historic quarters

Industrialisation, started with Industrial Revolution in mid 18th century by the invention of machines but advanced fast in early 19th century by establishing factories in large areas, has changed various aspects of life in terms of economy, architecture, design, and construction, rate of production, social life and politics. However one aspect, the nature, became very important in architecture field when there have been various and serious problems on four basic elements of planet: earth, air, water and fire. All these elements have been influenced badly after industrialisation period due to high demand for rapid and heavy construction regarding the all aspects above. Nowadays, in architecture it is inevitable to find a link between nature and construction, engineering and design to preserve the resources of life which can be called sustainability. This link is very essential in today's new architectural designs to sustain environment but it is more interesting and difficult to find the sustainable link for historical buildings which were constructed during economical revolutions. The structures were constructed with peculiar technology, serviceability in its own environment and definite district, as the time passes the possibility to withstand changing environment conditions would become complicated. In this paper, historical residential buildings, constructed in 19th century in Fener – Balat , , an important example of cultural heritage district, will be analysed in terms of three different views. First part is devoted to traditional construction techniques, materials and performances of them in building and urban scale in Fener ‐ Balat , the buildings were counted as hybrid structures due to its various materials and techniques during late 19th century, the streets were designed for pedestrians and coaches. The renovation and intervention strategies on performances will be discussed under this title. Second part is the obstacles and solutions for preservation of the area in order to have continuity of historical structure. Consistency of material, shape, architectural details of structures in broad sense urban tissue has been changing by new constructions in the area, occupying the old tissue of district like cancer cell. Besides physical destruction the area has faced another problem, social aspect caused by gentrification. Finally, rehabilitation and sustainability projects to preserve the historical area and consolidate buildings have been done until now are the third issue which will be analysed. Besides, the performances of structural and pathological intervention will be elucidated. In conclusion, possible sustainable suggestion in building and area scale will be listed for the area.

1

Papers

1. INTRODUCTION

In 18th century, the entire world have been affected by “Industrial Revolution”, which have continued to 19th and to 20th century with alterations on technological, economical, social and political dimensions of cities. Like every city, Istanbul, capital city of underwent an intense phase of economic, socio‐political and urban transformation aimed at the modernization of the old system. Ottoman Government had followed what was happening about the international industry developments and decided to bring the new technologies to country. Especially in the 19th century, many industrial buildings in almost all working branches were constructed in the Ottoman Empire by the government and the private sector (1). As a result of industrial revolution, economic and political developments marked important turning points in the history of the empire. Without any doubt first and important rearrangement law, is done by sultan not by public, unlike in French revolution (2).

Political, social and economic changes in Istanbul inevitably result in demographic growth and different urbanisation methodology opposite to vernacular one. Construction methods were carefully detailed in order to reduce the possibility of fires; in 1864, the government decreed that henceforth all construction in the capital was to be in stone or brick and with 1875 regulation divided the capital into primary and secondary zones. In the primary zones, timber construction was forbidden, while in the secondary zones, it was occasionally allowed provided that masonry fire walls were built (2). The 19th century residential buildings, constructed during the reforms to adopt European practices, show different construction techniques, use of functions, material and also bring a new concept of row‐ houses to country, in other words in 19th century residential building constructed with different way: row houses, multi‐storey masonry apartments and multi‐houses around a closed courtyard.

In Istanbul, it can be observed that in many districts masonry residential buildings were constructed in 19th century. These construction systems showing minor differences of architecture style and details could be observed in Kuzguncuk, Üsküdar, Kadiköy (Yeldeğirmeni) in Asian part of Istanbul, (Fener – Balat – ), Galata, Beyoglu, Ortaköy, Şişli in European part of city. Among these districts aforementioned, Fener – Balat region and historic structures were chosen for research on sustainable renovation due to several reasons. First of all, among the districts of Istanbul where 19th century masonry residential buildings are observed, Fener – Balat is the special district in terms of many aspects. In the area, homogenous architectural tissue have been preserved better than the other areas though these 19th century housings had been faced to be destroyed due to fast economic, social and politic changes like in other districts. Second reason of going ahead the research with case of studies from Fener – Balat Rehabilitation Programme is that all interventions were elaborated to be done carefully according to international charters. Next, choosing case studies from Fener – Balat ensure to analyze the conditions of residential buildings before and after rehabilitation programme. Buildings may show different behaviours after they had been undergone structural interventions compared to previous state which provides good occasion to propose future suggestions of sustainable development.

Therefore, Fener – Balat, an important example of cultural heritage district, will be analysed in terms of three different views. First part is devoted to traditional construction techniques, materials and performances of them in building and urban scale in Fener ‐ Balat. Second part is the obstacles and solutions for preservation of the area in order to have continuity of historical structure with possible green habitats. Finally, rehabilitation and sustainability projects to preserve the historical area and consolidate buildings have been done until now are the third issue which will be analysed.

2

Papers

2. GENERAL INFORMATION ABOUT AREA

2.1 Brief History

The area had been an important residential and place of resort by Genoese, Venetians and Europeans traders before 1453 when Istanbul was concurred by Fatih Sultan Mehmet. During the first years of Ottoman Empire, demographic changes can be observed in the area that some of local inhabitants left area whereas owing to settlement policy followed by Ottoman Empire in 15th century, Muslim Ottomans and Ottoman minorities such as Armenians and especially were settled in Fener area (3). The 17th century brought the Hagios Georgios Church, seat of the Greek patriarchy, which results in development and changes in terms of economy and architecture; as for Balat, the neighbourhood was inhabited by Jews to a large extent and by Venetians, Genoese and Armenians to a small extent in that period (4).

Moreover, 19th century residential buildings constructed during the reforms for adopting European practices, show different construction techniques, use of functions, material and bring a new concept of row‐houses (2). Therefore, the residential buildings as row housings in Fener – Balat were constructed in th th 19 century with technique of masonry, yet floors designed with timber materials. In 20 century, the most influential migration however occurred after the establishment of the state of Israel; one fourth of the Balat population left the neighbourhood. Despite the move of the prosperous families from the site, Fener preserved its character as a Greek neighbourhood until the 1960s when most of the Greek inhabitants left Istanbul in large numbers due to political reasons. Because of job prospects and low rents, the site became an important destination for new immigrants, mainly the people from the Black Sea region settled down in the area (4).

2.2 Characteristics and Rehabilitation of Area

Fener – Balat area, located in historical peninsula are surrounded by , transit road and Byzantine city walls in north; the buildings which were built recently in south; Greek Orthodox patriarch and important monuments of historical peninsula such as Bulgarian church in east; the church, and recent building in west.

During last twenty years, recent developments decision have been taken to improve the social and physical conditions of Fener ‐ Balat, counted as having the best preserved urban tissue of Istanbul. At the end of 1980, industrial buildings were removed and water of Golden Horn was purified and cleaned. Another important decision taken in HABITAT II, held in 1996 in Istanbul which affects the area directly was the necessity to start a rehabilitation project there. Therefore, Habitat II Conference initiated the Rehabilitation of Fener and Balat Districts Programme through the designation of these districts as UNESCO World Heritage Site. The projects started in 2003 and finished in 2007 with European Community and UNESCO Funds, aimed at recreating a viable, vital community while protecting the cultural heritage of district and restoration of two hundred housings (5), (6).

Moreover, European Commission, Fatih Municipality, French Institute for Anatolian Research and UNESCO carried out a feasibility research with the support of local Non‐Governmental Organisation’s Fener and Balat in 1997‐1998. The selected perimeter of Fener – Balat area for the possible regeneration programme covered an area of 16.2 hectare (including a built‐up area of 14.1 hectare and street space of 2.1 hectare) and the whole district includes 71 blocks (59 of which are totally inside the selected perimeter) and 1267 buildings .The outcome of this report can be summarised as following; in the selected perimeter there were about 20 buildings in ruins and the buildings on more than 240 lots were dilapidated. This means that about 20% of the physical stock was in poor conditions. Out of the 1401 lots on the selected area, out of the 1401 lots on the selected area, there were not buildings on 102 lots (7%), there were 68 vacant buildings (5.4%) and 124 partially empty buildings (9.7%) (7).

3

Papers

3. VERNACULAR ARCHITECTURE AND REVITALISATION

3.1 Material

The common construction material, used in the area is brick of which four different types can be noticed in area. Dina D’ayala, professor at Bath University also prepared a report on Fener – Balat housings. According to her report, the most common building material is the solid brick set in lime mortar to form two leaves masonry walls (88% of sample). Traditional extruded lightweight bricks, often used to wall up bay windows or at the upper storeys of buildings. Frogged brick imported from France have been observed in few cases, also in some very recent alterations, extruded brick tiles were seen as infill of reinforced concrete frames (8).

Apart from bricks, these resident buildings are also valuable that first industrial cast iron were used as girders and arch joists however during the times when constructions had been executing, the use of steel or namely cast iron was not approved a lot as a construction material owing to being a great innovation at that time, so these iron girders were tried to be hid. Finally a material of timber was used for flooring and the lightweight partition walls; wooden struts are set up and between these pillars wooden laths are nailed on which plasters are covered; this system is called Bağdadi (8), (5).

3.2 Traditional Construction Techniques in Fener – Balat

th It is possible to make generalization on 19 century historic dwellings in terms of dimensions of structural elements and peculiar functions with specific properties or with construction techniques in the buildings. The number of storey which is remarked in Fener – Balat historic masonry buildings may change between two to five. These structures, constructed as three dimensional masonry boxes whose behaviour is load bearing, exhibiting two common floor types, jack arch and timber joists and occasionally concrete slabs, on a stone foundation or without any footings in other words directly constructed on flat soil surface (9).

The thickness of the walls at ground floor is about 40 cm and then being reduced to 30 cm from the 3rd floor up to roof. Usually the wall is made up of a solid double leaf with sufficient through thickness connection. The foundation walls, made up of rubble stone masonry, in two sections of different thickness: the first under the road level, is about 90 cm thick and the second one, between the road and the ground floor structure, about 60 cm thick (8).

Floor structures are made of timber beams with variable dimensions, spanning between the two party walls parallel to façades in row‐house. The dimensions of joists can be classified as 10*7 cm if single or 12*5 cm if coupled, spaced at intervals of 30 to 45 cm. The timber joists might be clamped with metal elements on masonry wall in every three or four beams, sometimes visible from outside. The joists are covered usually by planks and linoleum sheets or tiles at top. Less common solution is timber joists with planks and screed and tiles above (8), (9).

Another relatively common structure is represented by iron beams and jack arches noticed at flat roof where the inhabitants use it as terraces and rarely at the lower storey in the building as a store. The beams have a depth of 10 cm, and they are spaced at 75 cm apart with shallow arches formed by brick tiles 30*15*6 cm. A forth type of structure is made of a concrete slab without beams (8).

An important architectural feature of these buildings are bay windows, different architectural terminology can be named to these elements as jetty, chumba, oriels. Bay windows are supported either by iron girders which encircles the extended part or by more than one iron beams in the system of arch joists.

4

Papers

Figure1: Traditional techniques in Fener – Balat and bay window details.

3.3 Principal Elements of Strategies

The area has been defined and analysed in terms of the obvious and concrete borders surrounding it; taxonomy of construction materials and techniques observed in vernacular architecture; functional and historic identity depending on economical vitality were mentioned until now however in order to provide social and physical sustainable revitalization for area without giving any damage on social and urban fabric, necessary element of possible strategies should be analysed.

Historic properties of the areas consists of architectural value, social value, cultural value, aesthetic value, historic value, urban context value forming multiple value layers of elements for its community however commercial and economic value also sustainable factors may not be prefered during conservation of historic districts due to legal land use planning that restricts physical changes and demolition, named as public intervention. On the other hand, this critical approach without tangible tools is difficult approach of rehabilitation unless it is applied considering welfare of community. As a result, the market may not preserve buildings and the inhabitants tend to find that there is no worth for retention whereas only economic and commercial values also cannot be during revitalisation process, without multiple value layers especially social and historical ones, it would turn into gentrification. Economical and commercial value can be satisfied four essential characteristics: scarcity, purchasing power, desire and utility (10). Historic buildings always show scarcity due to their unique and different structures than modern world but it is not easy distribute that vantage to all buildings in area. Purchasing power exist in different levels however desire and utility are the most vulnerable aspects which are often lacking for historic buildings. In Fener – Balat area, after the departure of minorities in 20th century, the buildings were owned by lower income immigrants from Black Sea Region and South East Anatolian Region (4). Therefore the desire of users which would be against functional and financial utility had been arisen. The danger of obsolescence involving both buildings and area scale appeared; the tendency among inhabitants to have no utility, no desire and no claim on area were observed. As mentioned above, the rehabilitation works funded by international and local organizations were done aiming regain of desire for the area and reduce diminution level of historic structures by social and physical enhancement tools.

5

Papers

On the other hand, accessibility to area has been transformed in the course of time with rapid urban growth due to industrial developments in city at 19th century, the demands of transportation networks and increase in the number of vehicles (1). While the historic area and buildings had been constructed, human mobility inside the boundaries of Fener ‐ Balat and accessibility to area can be considered as sustainable if it is compared to current network. The streets had been designed for pedestrians and horse carriages in 19th century, now served for more fast transportation vehicles, causes not only dissonance with urban fabric and inconvenience by high mobility in narrow streets but also affects nature and material with high amount CO2 emission. Transportation policy through and within the area should be reconsidered in order to reduce undesirable actions which affects urban fabric of historic district.

Another dimension of obsolescence for building in historic areas, physical and structural aspects of obsolescence will be reviewed briefly with Fener – Balat area. Historic buildings may deteriorate through the effects of time, the condition of ground, temperature and climate, traffic vibration, earthquake or poor maintenance activities. Functional qualities of structure also indicate the necessity of rehabilitation of building because building fabric may not meet the requirements of demands of users. If the building does not have heating and cooling systems; modern telecommunication infrastructure and technological design cause functional obsolescence and thus abandonment by users. In the area, the factors which cause decay of historical monuments are lack of care, improper repair, abandonment, vandalism, traffic, public works, air pollutions which can titled under the reasons caused by man. All factors which were mentioned directly or indirectly have been influenced the residential buildings in area. During the construction of Haliç Collector in 1986, a few of historical buildings were damaged severely and cracks were appeared in some of buildings. Critical buildings were destroyed after geometric survey of them had been done (9). Moreover, the inhabitants of the Fener‐Balat districts has suffered from various physical and environmental problems, such as the buildings and streets in poor conditions, environmental and air pollution, inadequate infrastructure and cleaning services. The majority of the inhabitants mostly complain about the low quality of life in the district, which is mainly caused by the buildings in poor conditions; and they first wished the restoration of the buildings (4). Therefore it is inevitable to observe serious damages, pathological problems, and improper maintenance activities due to several dimensions of area.

4. PRESERVATON OF AREA

th Migrations of Ottoman Greek, Jewish and Armenians from area and demographic variations in late 20 century lead to fast and radical changes in Fener – Balat. In this part of study, the problems which had been observed in Fener – Balat before the rehabilitation programme, 2003 and also current ones despite of endeavours will be analysed only from physical and architectural point of view; the other factors: political and economical aspects are not main interest of this part.

4.1 Preservation Problems in Area

Location of structure can accelerate deterioration due to climatic effects; building constructed in water course or on slope of hill can be exposed deterioration intensely. Also, buildings on outskirts of mountains and on valley are prone to floods if the precautions are not taken (11). In Fener – Balat area, buildings cannot be accumulated under a unique title considering relationship between climate and topography. Some were constructed near Golden Horn, Marmara Sea; some were located on inclined slopes and the other on the fifth hill of Istanbul. Inland the land rises above sea level and consists of sedimentary type carboniferous rock. There is a labyrinth of narrow streets in the old quarters with steep slopes and sidewalk steps that wind upward to the hill. The slope of the land presents a problem in mitigation efforts on damage unless there is efficient infrastructure sanitary sewage and drain protection. The characteristic of soil was found as made – up soil which affects the structure stability and behaviour under dynamic and static loads (6).

6

Papers

In Fener – Balat, decay of material due to humidity, corrosion, lack maintenance, soluble salts can be seen; typical pathologies observed are: efflorescence, loss of surface material, loss of mortar. The houses traditionally do not have dump courses, and very often recent repointing or replastering with cementitious material are to be considered responsible for the occurrence of the efflorescence and the eventual loss of material (8). Bay windows of buildings may show deterioration in way that the bay window elements are supported by iron stanchions sometimes covered by plasterworks. The plasterwork on the bottom surface of bay window has also been broken and the weather effects coming into floor system of the bay window (barrel vault or timber beams) have caused great damage (12). Spans between party walls and the facades of these buildings can only relay on the frictional restraint provided by the party walls themselves if the toothing of the brickwork is adequate. While this can be sufficient in preventing overturning in modest tremors, it becomes ineffective for higher shaking, especially at the upper storey. In the case of Fener and Balat the most common chosen solution to the problem of out‐of‐plane restraint of the façade is the introduction of iron ties (8). Therefore, existing iron tie‐rods, which are probably present in all buildings, require to be protected from corrosion otherwise there can be stability problem in the area.

Climatic and environmental effects has resulted in the decay of the material and alteration the physical and chemical properties. The damages in the structure make the structure vulnerable to any further actions which accelerate the deterioration process and threaten the stability of structure. In Fener – Balat housings, due to temperature differences and freeze and melting cycles, materials are deformed. In hot summer, materials elongate where as in cold winter they are exposed to freezing. Capillary rise of water in masonry buildings can cause failure in materials.

Other natural actions which may harm historical buildings are natural hazards caused by earthquakes, floods, eruption of volcanoes, landslides, tornados, strong winds etc. Among these, earthquake and potential flooding are the major risk that should be concerned about historical structures in Fener ‐ Balat. The construction type of the buildings is masonry, prone to damages under dynamic forces because masonry has a relatively large compressive strength but only a low tensile strength.

The other problem which may be faced in the area is the behaviour of buildings, constructed as row‐ houses under dynamic forces. Row houses, made up of multiple residences joined together with common walls show complex behaviours during earthquakes. In row structures containing walls common between residences, aggregate problem has the potential to cause collapse especially when floor or ceiling diaphragms in adjacent residences are misaligned. Different heights for the lateral force transfer into the common wall can result in punching shear failure of the wall or diaphragm detachment and collapse. A row structure, despite behaving in an earthquake as a single interconnected structure, may be perceived as different buildings by engineers and architects so it is essential to perform remedial work on an entire row structure at one time instead of an isolated structure.

4.2 New Construction Materials

Historic civil architecture is an important element of cities which reflects its social, cultural, economic values and besides lifestyles of people living in past. Although, inside the city residential buildings are majority in number when they are compared to other buildings, they are more vulnerable to be destroyed when there is sudden or strong reason to change social, political, economic situation of city. As a result residential buildings are needed to be preserved carefully. Other buildings especially the religious ones are conserved by the consciousness of public due to respects to religions, states or governors on the other hand when there is new technology or contemporary material or trend for building construction, historic buildings would be obsolete unless conservation techniques are taken both in the area and building.

After the second half of 19th century, reinforced concrete construction have spread rapidly after the developments and reports published by German and Austrian engineers (13). The historic buildings

7

Papers when they likely become obsolete considering aforementioned dimensions, rehabilitation and revitalisation process are not chosen as solution all the time and buildings encounter to be destroyed when four elements scarcity, purchasing power, desire and utility lose the significance which is totally opposite to the concept of preservation, historic structures become more prone to be ignored. Moreover, in Fener – Balat area this kind of transformation can be noticeable; in masonry row houses, an individual housing or sometimes more than one constructed by different kind of material and techniques may exist. Consequently, changing integrity of row housings not only ruin architectural and aesthetic value also affects structure behaviour under dynamic and static loads, thermal performances of whole system and economic public value, are directly related to sustainability of preservation. In order to have sustainable solution in historic areas, minimum deterioration should be aimed and relevant strategies also intervention are taken considering economical, social and environmental aspect individually.

Figure 2: Traditional and different construction techniques in row – houses in Fener – Balat (Personal Archive: E. Kishali).

4.3 Gentrification Problem

Fener – Balat Rehabilitation Programme is a unique and multidisciplinary project for a specific historic Turkish area owing to considering social and public interests. On the other hand, in other districts of Istanbul by changing hands of buildings had started a process to attract upper social classes, income groups and cultures, called gentrification. Furthermore, this process may be titled as a restoration simultaneously with intervention actions which are completely against article 9 of Venice Charter; it was stated that “The process of restoration is a highly specialized operation. Its aim is to preserve and reveal the aesthetic and historic value of the monument and is based on respect for original material and authentic documents.” (14). In order to promote and revitalise the historic areas just focusing on commercial enhancement yet neglecting social, architectural, physical and sustainable value can be titled as conservation or refurbishment, should be accepted for historic quarters.

Important precautions were taken to prevent the area as possible gentrification area, it was stated that one of big problems is ensuring that the rehabilitation of this area does not turn it to the expulsion of poor tenants. To achieve it, precaution was taken, to maintain the low rents during the next five years with agreements between landlords and the project authorities however there was no defined planning activity what they will do when the agreement period ends (5). On the other hand, in 2009, with the decision of Fatih Municipality council, new project on Fener – Balat‐ Ayvansaray has been accepted. The aim of the project is serving all necessary conditions of gentrification aforementioned and it would be performed by retaining the facades; re – constructing the buildings and changing the social structure into upper class (15). At the moment, local users are trying to resist the project however more organisations are needed for relinquishment.

8

Papers

5. REHABILITATION AND RESTORATION OF AREA

In this part, performances of buildings and structures are analysed with sustainability perspective. Analysing performances of buildings before and after rehabilitation project is essential in order to indicate the benefit of interventions. In this part performances of structure and pathology of building components will be analysed and exemplified by Fener – Balat houses.

5.1 Performances of Structures

Historical masonry buildings should be understood very well in order to make successful assessments and interventions. The behaviour of masonry is influenced by three main factors: the shape and the connections of the structure; the construction materials and its behaviour under loadings; the imposed forces, accelerations and deformations. Structural analysis of masonry historic structures is difficult task because of various reasons. First one is large variability of mechanical properties, due to workmanship and use of natural materials. It is not easy to have homogeneous value about mechanical properties of materials. Secondly significant changes in the core and constitution of structural elements, associated with long construction periods. In course of time, structures might have been undergone various changes which lead to different behaviour which is expected from recently constructed masonry buildings. Next reason of difficulties in analysis of masonry buildings is that construction sequence of historic structures is unknown. The constructions of old buildings especially the huge structures such as , churches, palaces, last very long time. Finally, the inconvenience of restoration old buildings is that new regulations and codes cannot be applied to them. These codes were written for new buildings in order to have optimum standards in serviceability on the other hand already constructed buildings may not show same desired performance as stated in modern norms.

Moreover, earthquake is an important issue for Turkey which have suffered it for the centuries. Although it is a natural phenomenon, damage and loss of spiritual and material make earthquake to be seemed more difficult to handle. Inhabitants who are living in a place, highly vulnerable to seismic actions may be injured or killed through the shelters having been constructed in different forms, shapes and techniques. Therefore, the resistance behaviour of structure under dynamic forces is necessary to minimise the possibility of hazardous effect on human life. Material, construction technique and soil conditions are basic elements which may change the behaviour of building under dynamic actions. Besides, the earthquakes, which cannot be predicted in time and intensity, may cause major structural damage, and the collapse of historical buildings and monuments. Whenever an earthquake occurs more attention to the great monuments has been given rather than the vernacular architecture which constitutes the urban fabric. On the other hand, intensive care of vernacular architecture under dynamic loads would save not only money but also lives. Istanbul is one of the cities, located on the Northern Anatolian fault line, can anticipate having severe earthquake (16).

During rehabilitation programme, thirty one buildings were undergone extensive repair and consolidation process. One of the buildings, chosen from area, was analysed by using finite element methods before and after interventions. Before the building underwent interventions, as other buildings in the area showed some structural problems, needed to be analyzed in details. For chosen case study the deep crack in one of party wall, additional spaces constructed recently and enlarged balcony on bay window influence the mechanical resistance of structure and material. Under rehabilitation programme, rebuilding of walls where deep cracks were observed; stitching, taking out cracked masonry at intervals up the crack and replacing them with new stones or bricks; and removal of unqualified additional parts such as kitchen, bathroom were chosen as a rehabilitation solutions for the structure (6). In figure 3, the modal analysis outcome is represented; before restoration, for the first modal the mass participation ratio was 69 % whereas after interventions box effects which means more stability was satisfied and mass participation ration has been increased to 88 %.

9

Papers

Minimum damage to nature within acceptable social and economic influences on inhabitants is indispensable factor for engineers and architect who are involved in historic structures. Furthermore, the decision and type of minimum intervention principal for restoration of architectural heritage not only is needed for preserving authenticity construction but also for planning future behaviour and sustainability.

Figure 3: Modal analysis of buildings before and after interventions.

5.2 Performances of Buildings: Pathology

Material pathology analysis represents the anomalies of buildings which have been developed in course of time is an overall view of buildings from the observations. It is dispensable to show these entire pathological problems on old buildings before the further steps. Since the pathological problems were divided into two parts as material and structural, the reasons which may cause them should be understood. Alteration, degradation, fissures and deformations of buildings are categorised in this phase. In order to evaluate performances of buildings after interventions in terms of sustainability and pathology, the buildings are better to be analysed by non – destructive tests depending on the aim of performance. In this part only visual observations will be presented to show the importance of sustainable solutions and importance of applications. Prevention of rain flow on facades, the proper details of window sills, and solutions for rising damp from grounds can be listed as observed precautions should be done without performing any tests. In Figure 4, the pictures show two different applications of window sill and pathological anomaly; not matter if window sill is present, only the component is not sufficient there should be little cavity under sill to hold water to prevent flow of rain on facade. The successful intervention techniques on structural behaviour should be satisfied also in building pathology since the materials used on restoration should sustain.

Figure 4: Examples from Fener area showing building pathology (Personal Archive: E. Kishali).

10

Papers

6. SUGGESTIONS AND CONCLUSION

There are important points are considered if sustainability of architectural heritage is desired. Structural, building repairs and interventions are ought to be decided considering ability to continue with minimum long term or permanent effect on natural and social life. Moreover, responsibility of transmitting the cultural heritage to next generations makes building sustainability more important.

The historic building from Fener – Balat area represent some important aspects when the revitalization of area is desired. Revitalization of area has multi dimensions and wide range of aspects: structural, social, economical and technological. Possibility of introducing minimum intervention to historic structures, availability of using traditional techniques and materials, reversibility of methods, importance of strengthening way of buildings against to seismic actions and wide approach rather than focusing on single building in row housings are constitutes the basic for sustainable preservation. Moreover aggregate problem may raise a problem if the individual buildings in row houses are restored and consolidated. Individual stiffening of one building from row‐house may increase the danger of damage during earthquake because of the fact that other adjacent structures oscillates within their usual periods whereas consolidated structure, stiffer one, tries to dissipate all energy by itself. Therefore, in Umbria, Italy, there is a regional law provides a rational guide to vulnerability analysis and to reinforcing interventions of aggregates. The law deals with the aim for detailed analysis of the building aggregates and not of single buildings, considering both the wall connections and masonry (17).

The social aspect of area, the danger of gentrification is big problem when inhabitants are expulsed from buildings by increasing the land value and locating high upper class in terms of economy. This kind of process is not accepted as sustainable rehabilitation since social integration to conservation will not be satisfied furthermore, if economical enhancement with new functions and high income groups do not serve existing social structure, it should be avoided although rehabilitation techniques are done according to international charters.

New transportation and environment policy in area can be suggested for sustainable historic quarters by reducing vehicle inside area. The streets were designed in 19th century for pedestrians and coaches, nowadays motor vehicles creates mess and emits more gases to nature. The transportation network depends on also the slope of area, therefore it can be suggested that in flat parts of area, bicycle paths and partial traffic for motor vehicles with any kind of barriers or different road tissues on streets would prevent dangerous effect of traffic.

ACKNOWLEDGEMENT

The authors wish to thank B. Alpagut, B. Altınsay, G. Köksal and E. Rosina for their precious contributions.

REFERENCES

(1) Köksal, G. (2005). İstanbul'daki Endüstri Mirası İçin Koruma ve Yeniden Kullanım Önerileri. PhD. dissertations unpublished manuscript. Istanbul Technical University, Istanbul, Turkey.

(2) Çelik, Z. (1993). The Remaking of Istanbul, Portrait of an Ottoman Capital in the Nineteenth Century. University of California Press, Berkeley, United States of America.

(3) Budak, B. (2007). Kentsel Yenileşme Süreci Bağlamında ‘Soylulaştırma’: Fener‐Balat Örneği. Msc. dissertations unpublished manuscript. Mimar Sinan University, Istanbul, Turkey.

(4) Düzcü S. (2006). In Partial Fulfillment of the Requirements for the Degree of Master of Science in Urban Design in City and Regional Planning. Msc. Dissertations unpublished manuscript. Middle East Technical University, Ankara, Turkey.

11

Papers

(5) Ergün, N. (2004). Gentrification in Istanbul. Cities Volume 21 No: 5, p. 391 – 405. Great Britain: Elsevier.

(6) Altınsay, B. (Local Co‐ordinator of Fener – Balat Rehabilitation Programme)(Personal Communication, 27 August 2009)

(7) Fatih Municipality, European Union, UNESCO, French Institute for Anatolian Studies (1998) The Rehabilitation of Balat and Fener Districts, Analysis and Regulation Proposals.

(8) D’Ayala D. (2003). EU‐Fatih Municipality Programme: Rehabilitation of Fener and Balat Districts. Seismic vulnerability and strengthening of historic building, in Fener and Balat Districts, Istanbul, Turkey

(9) Kaptı, M., Ökten, M. S. (2001). Proceedings of the 3rd International Seminar “Historical Constructions 2001 possibilities of numerical and experimental techniques”: The structural systems of semi‐masonry houses built at Fener (Istanbul) in 19th Century. Guimarães, Portugal: University of Minho.

(10) Tiesdell, S., Oc, T. and Heath, T. (1996). Revitalizing Historic Urban Quarters, Oxford; Boston: Architectural Press.

(11) Ahunbay. Z. (2004). Tarihi Çevre Koruma ve Restorasyon. Yapı Endüstri Merkezi Yayınları (YEM), Istanbul, Turkey.

(12) Kaptı, M. (1998). İstanbul'da 19.Yy Sivil Kargir Mimarinin Korunması için Fener Bölgesi Örneğinde Bir Yöntem Geliştirilmesi. PhD. Dissertations unpublished manuscript. Mimar sinan University, Istanbul, Turkey.

(13) Ersoy, U., Özcebe,G. and Tankut,T. (2003). Reinforced Concrete. Middle East Technical University Ankara, Turkey.

(14) ICOMOS (The International Council on Monuments and Sites) (1964) Second International Congress of Architects and Technicians of Historic Monuments. Venice, Italy.

(15)Arolat E., (2009). Emre Arolat'in projeye bakışı. Retrieved from on 25 February 2009 http://www.febayder.com/content/emre‐arolatin‐projeye‐bakisi

(16) Kishali E., (2009). Congresso Coordinamento Dottorandi e Dottori di Ricerca in Architettura Tecnica. “Residential Building Morphology and Construction Techniques in Seismic Area: Fener ‐ Balat ”. Messina, Italy.

(17) Binda, L., Saisi, A., Tiraboschi, C. (2000). Construction and Building Materials. Investigation procedures for the diagnosis of historic masonries. Volume 14, 199 – 233. Elsevier.

12