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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 Evaluation of wooden structures(Springer, 2019) Koca, GülruIn order to preserve the architectural heritage and sustainability of cities, the accurate evaluation of the mechanical properties of existing buildings is crucial. While inorganic building materials such as natural stones can be evaluated more easily, it is difficult to accurately assess the mechanical properties of wood. Mistaken evaluations of structural wooden members may lead to large-scale replacements in the maintenance and restoration of buildings. The techniques used in the evaluation of wood are; destructive, semi-destructive and non-destructive tests. Although destructive tests give accurate information about the mechanical properties of wood, they are not preferred in the evaluation of the existing structures because they cause the loss of structural integrity. The semi-destructive and non-destructive methods are being widely used for the last decades in the evaluation of structural wooden members. As these techniques do not give harm to the structural members, they allow the in situ evaluation of wooden structures. While semi-destructive tests are carried out with the extraction of a small piece without influencing the mechanical properties of wood, non-destructive techniques are carried out with the help of small devices in order to detect the interior defect and deteriorations. In this study, it is aimed to give information about some of the most used semi-destructive and non-destructive test methods.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 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.
