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Öğe A practical modification to coaxial cables as damage sensor with TDR in obscured structural members and RC piles(Techno-Press, 2023) Ozgur, Mehmet; Arsoy, SamiObscured structural members are mostly under-evaluated during condition assessment due to lack of visual inspection capability. Insufficient information about the integrity of these structural members poses a significant risk for public safety. Time domain reflectometry (TDR) is a novel approach in structural health monitoring (SHM). Ordinary coaxial cables as is without a major modification are not suitable for SHM with TDR. The objective of this study is to propose a practical and cost-effective modification approach to commercially available coaxial cables in order to use them as a cable sensor for damage detection with the TDR equipment for obscured structural members. The experimental validation and assessment of the proposed modification approach was achieved by conducting 3-point bending tests of the model piles as a representative obscured structural member. It can be noted that the RG59/U-6 and RG6/U-4 cable sensors expose higher strain sensitivity in comparison with non-modified as is versions of the cables used. As a result, the cable sensors have the capability of sensing both the presence and the location ofa structural damage with a maximum aberration of 3 cm. Furthermore, the crack development can be monitored by the RG59/U-6 cable sensor with a simple calibration.Öğe Assessment of Soil-Structure Interaction in Reinforced Concrete Buildings Based on Structure to Soil Stiffness Ratio(Afet ve Acil Durum Yonetimi Baskanligi (AFAD), 2023) Ozgur, Mehmet; Bozdogan, Kanat BurakSoil-structure interaction (SSI) results in higher structural damping ratio and elongated fundamental natural period of the building. Generally, these modifications on dynamic properties of the building are regarded to be favorable for dynamic response and SSI is neglected in most of the design codes. However, extensive research points out that neglecting the role of SSI can be a misconception that lead an unsafe design by underestimating the rotational ductility demand and top displacement of the building. Therefore, it is essential to determine if SSI is expected to be significant for safe design of the buildings. In this study, the significance of SSI in design is assessed with the help of the structure to soil stiffness ratio that is considered as the most important parameter controlling the period elongation. Stiffness ratio is determined for buildings with moment-resisting frames and varying number of storeys resting on different soil conditions and a threshold of 0.1 is assumed as the critical value that yields a period elongation of 5%. It is shown that, SSI should be taken into account for buildings founded on site classes ZE, ZD and ZC and can be neglected for site classes ZB and ZA. © 2023 The Author(s).Öğe Çok Katlı Betonarme Bir Binanın Altsistem Yaklaşımı İle Analizi(2023) Taştan, Hüseyin; Ozgur, MehmetÖz – Türkiye, bulunduğu coğrafyada ki aktif faylar sebebiyle sıklıkla büyük depremler ile yüzleşmekte, can kayıpları yaşanmakta ve maddi hasarlar oluşmaktadır. Bu bakımdan yapı tasarımında, deprem kuvvetini etkileyebilecek tüm parametrelerin göz önünde bulundurulması ve hesaplamalara dahil edilmesi oldukça önemlidir. Bu çalışmada, kazıklı temel sistemine sahip betonarme bir yapı ile temel zemini arasındaki etkileşim incelenmiştir. Zemin-kazık-yapı etkileşimi, altsistem yaklaşımı “Yöntem I” ile hesaplamalara yansıtılmış olup üstyapı, temel ve kazıklarda iç kuvvet, yer değiştirme ve şekil değiştirme talepleri elde edilmiştir. Sonuçları mukayese edebilmek için aynı yapı, kazıklara tanımlanan yatay yatak katsayısı yayları ile tasarım spektrumu etkisinde analiz edilmiş ve son olarak ise etkileşimsiz durumda ki sonuçlar için yine aynı yapı zemine ankastre mesnetli şekilde modellenerek hesaplama yapılmıştır. Her üç yöntemden elde edilen sonuçlar mukayese edilerek zemin-kazık-yapı etkileşimi irdelenmiştir.Öğe Development and validation of a degree of saturation prediction model using time domain reflectometry for compaction control(Elsevier, 2023) Ozgur, MehmetCompaction quality is directly related with the shear strength of soils. Inadequately compacted soils have lower shear strength that decrease the load bearing capacity and increase the differential settlement of the pavement, which may endanger safety and durability of the highways. Although intelligent compaction technology has enhanced the quality control of the compaction, conventional evaluation methods adopting sampling from random locations to determine relative compaction are extensively used in most of the earthwork projects. However, relative compaction may lead misjudgment, since the compaction energy level and the soil type inplace cannot match exactly with the given specifications of an earthwork project. Recent studies have shown that soil degree of saturation (Sr) can be utilized as an alternative control parameter for compaction quality. Sr inplace is usually determined with sand cone method. The method is time consuming as well as prone to error due to potential water seepage and deformation of soft soils. With its ability to provide remote and continuous monitoring in real time, Time Domain Reflectometry (TDR) has the potential to serve as a viable alternative method for determination Sr in-place. This research presents models developed using different calibration methods for the prediction of Sr with TDR measured dielectric permittivity. The accuracy of the models was evaluated with cross-validation. The results show that TDR is able to predict the Sr with less than & PLUSMN;5% deviation for 93% of the specimens in the validation set within the saturation ratio range of 0.01-0.93 cm3 cm-3 with an appropriate model.
