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Yayın Using the ultrasonic stress wave technique to evaluate structural timber members of an old masonry building(Kastamonu Univ, Orman Fak, 2018) Koca, Gülru; Dündar, Türker; As, NusretAim of study: The main objective of this study is to evaluate the current state of the structural timber members of an old masonry building by using destructive and non-destructive test methods and to determine the efficiency of non-destructive test methods by obtaining correlations between destructive and non-destructive test parameters. Area of study: Specimens were extracted from different parts of an old semi-detached masonry building in Istanbul, Turkey. The building was built at the beginning of the 20th century in Kadikoy, a residential district in the Asia side of Istanbul. Material and Methods: Ultrasonic stress wave test was carried out on specimens prepared from the structural members. Following the ultrasonic based non-destructive tests, the bending strength and modulus of elasticity in the bending tests were determined for the specimens. Main results: According to the results of the experiments, it was observed that the regression correlations were high for the softwoods (fir and spruce), but relatively lower correlations were obtained for the chestnut specimens. Highlights: Because of the good R-2 values obtained between the MOED and mechanical properties of the softwoods, the non-destructive stress wave technique can be recommended for the evaluation of softwoods in structures. Although chestnut showed very good mechanical properties, a satisfactory evaluation of the chestnut members could not be obtained because of the small number of specimens. Further investigation is needed with large sample groups.Yayın The effect of cyclic relative humidity exposure, sanding and grooving on the dimensional stability of solid wood parquet(Istanbul Teknik Universitesi, Faculty of Architecture, 2018) Koca, Gülru; Arıoğlu, Nihal; As, NusretIn this study, the effect of cyclic relative humidity changes, sanding and grooving on the dimensional stability of solid wood parquet were evaluated. The experiments were carried out on oak (Quercus petraea) and sapele (Entandrophrag-ma cylindiricum) wood species. Firstly some physical tests (density, shrinkage, and swelling) were carried out on 20×20×30 mm specimens obtained from these two species. After the physical tests the parquet size specimen groups were obtained both in radial and tangential section directions and in two sizes; narrow (250×50×15 mm) and wide (250×90×15 mm). One group of parquet size specimens was sanded and the other group was grooved. There was also a group of specimen for control. After being conditioned to equilibrium moisture content at 65% relative humidity, specimens were placed in a climate chamber and exposed to cyclic relative humidity changes. The dimensions of the specimens were measured between different environmental conditions and the dimensional change was evaluated by taking into consideration the mentioned physical properties. The results show that cyclic relative humidity changes mainly resulted with an increase in the dimensional stability of sanded and cyclic conditioned specimens. There was not a significant change in the dimensional stability of grooved specimens.Yayın Masif ahşap parkelerde geometrik kararlılık üzerine bazı faktörlerin etkisi(Istanbul Univ, Veteriner Fakultesi, 2013) Koca, Gülru; Arıoğlu, Nihal; As, NusretBu çalışmada; masif ahşap parkelerin geometrik kararlılığı araştırılmıştır. Ahşap parkelerin bünyesindeki geometrik değişimlerin incelenmesi amacıyla iki ağaç türünden iki farklı genişlikte elde edilen numunelere ön deney ve deneyler uygulanmıştır. Ön deneylerde numunelerin yoğunluk, radyal ve teğet doğrultuda genişleme ve daralma değerleri belirlenmiştir. Deneylerde numuneler farklı bağıl nem değerlerinde şartlandırılıp geometrik kararlılıkları belirlenmiştir. Bu aşamada numunelerin bir kısmına oluk açılmış, bir kısmı sistire edilip her işlemin ardından tekrar şartlandırılmıştır. Oluk açılmayıp sistire edilmeyen bir numune grubu da ardışık olarak şartlandırılmıştır. Deneylerin ardından numunelerin geometrik değişimleri elde edilen literatür bilgileri ve yapılan istatistiki test bulgularıyla birlikte değerlendirilmiştir. Sonuçta; parkelere oluk açılmasının geometrik kararlılığın iyileştirilmesinde fayda sağlamadığı; fakat sistire edilip ardışık döngülere tabi tutulmasının geometrik kararlılığın artmasına etki ettiği ortaya konmuştur. Ardışık olarak farklı iklim koşullarında kalan malzemenin geometrik kararlılığında genel olarak artış olduğu da bir diğer sonuçtur.Yayın Earthquakes, sustainable settlements and traditional construction techniques(Mehmet Topçu, 2023-12-31) Koca, GülruUrbanization is increasing all around the world due to population growth and big cities receive a high volume of migrants due to economic and social reasons. However, rapid population growth should be prevented in big cities in order to provide comfortable living conditions to the population. When urban planning practices do not catch the speed of urbanization; the tendency towards vertical architecture increases, the amount of green space decreases and problems related to unplanned urbanization come to the fore. These important problems, which have considerably increased recently in Türkiye, may lead greater problems in many respects. The parallel and self-sufficient development of urban and rural areas, which is defined as urban sustainability, is considered as the best-case scenario in urban planning practices. This aim is adopted nowadays by most of the countries in the world as it prevents rapid population growth in cities and depopulation in rural areas. Decisions which are taken to ensure urban sustainability are important for all countries. However, these decisions become even more important in regions with disaster risk. As the majority of Türkiye’s land area is under seismic risk, the problems which may arise due to rapid urbanization during an earthquake should be prevented. The damage and losses which could occur during an earthquake and the security, health, education problems which will arise after the earthquake can be solved by preventing dense housing and uncontrolled migration in urban areas. The connection between urban and rural areas should be strengthened. Besides, the social and economic sustainability of the rural area should be ensured. Settlements should be designed away from fault lines with a holistic approach as “living spaces” which consist components such as; transportation, infrastructure, green spaces and educational spaces. Additionally; the use of appropriate construction techniques and materials should be accepted as a priority. In this context, it can be mentioned that traditional building techniques, which have been developed over centuries and whose deficiencies have been improved during this period, should be preferred especially in rural areas. In this study, the criteria that gain importance in the construction of earthquake resistant and sustainable settlements are evaluated on Türkiye case. The precautions which should be taken to ensure rural sustainability and to prevent the depopulation of rural areas are emphasized. Within this scope, the importance of protecting the architectural texture and regenerating traditional building culture was discussed in constructing earthquake resistant settlements.Yayın Evaluation of traditional Sirince houses according to sustainable construction principles(Selcuk Univ, 2019-06) Koca, GülruSirince is a village which has unique traditional building samples and which is heavily influenced by the influx of tourists in the summer season for the last decade. Many buildings in Sirince have changed function due to tourism activities and a significant amount of them have been renovated. Besides, some new buildings has been constructed from modern building materials such as reinforced concrete in the settlement. Since the management plan has not yet put into force in the region, excessive interventions can be seen in renovations and restorations. However, the settlement is still facing a decrease in population for some reasons. In order to preserve the population of Sirince the sustainability of the region has to be ensured and the existing historical and architectural texture has to be preserved. This study mainly focuses on the evaluation of Sirince according to sustainable construction principles and suggests some interventions in order to increase the sustainability. As a first statement it can be mentioned that, tourism has to be viewed as a means rather than an end to improve the sustainability of the settlement. The constructions has to be carried out according to ecology based principles, a healthy built environment has to be created and non-renewable natural sources has to be used efficiently to increase the sustainability in constructions. Excessive restoration interventions has to be prevented, traditional materials and techniques has to be preserved. Reusing and recycling of materials has to be evaluated in order to make environment-friendly applications.Yayın Earthquake resilience of densely populated settlements: a strategic approach to mitigate Istanbul’s earthquake risk(Mehmet Topçu, 2025-04-30) Koca, GülruOne of the most significant challenges confronted by earthquake-prone cities results from the urban planning strategies and interventions preferred during the construction and development efforts. The planning of infrastructure that will serve the increasing population is even more important, especially in cities that have historical importance and have evolved into large metropolises in a short time. Proper planning and renewal efforts that align with earthquake-resistant urban development strategies not only add value for all stakeholders but also help avoid significant material and moral losses caused by poorly planned urban development. Although earthquake-prone settlements have thousands of years of construction traditions, these traditions have often been replaced by modern construction techniques nowadays. In cities where the transformation from traditional to modern construction techniques is rapid and uncontrolled, a severe earthquake is more likely to cause a significant damage. Türkiye has a high earthquake risk due to its geographical location. The Main Marmara Fault is an active fault line that poses a serious threat to Istanbul. The devastating earthquake series along the East Anatolian Fault in February 2023 have once again highlighted the urgency of taking necessary precautions and preparations for the anticipated Marmara earthquake. Istanbul is one of the most historically significant metropolises in the world. Accordingly, the city has expanded by receiving immigration since the last major earthquake. Given its unique place in world history and its centuries-old role as the capital of great civilizations, it is crucial to ensure the seismic resilience in Istanbul to protect both the lives and property of its dense population and to safeguard its cultural heritage sites. The aims of this paper are to evaluate the current characteristics of Istanbul in the event of a possible earthquake, to identify potential challenges of the city and to put forward a strategic approach to improve seismic resistance of the city. The evaluation was carried out by conducting a SWOT analysis based on the physical, environmental, social and economic conditions of the city. For this purpose, firstly the previous and current urban design practices adopted in the city was evaluated. The key features effective in the construction of an earthquake resilient settlement was emphasized and taken into consideration. Besides, the crucial stakeholders and their potential contributions were also evaluated. In this context, the problems that needs to be improved are revealed and a conceptual framework of an urban planning strategy is presented to construct an earthquake resilient city that provides satisfaction to all its stakeholders.
