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Ultrasonic Shear Wave Tomography (USWT) is recommended as a modern non-destructive method that uses ultrasonic shear waves to detect objects, interfaces, and anomalies in the structure. The entire structure can be analyzed quickly and economically without destruction of any structural element. Thus, ultrasonic transition properties can be visualized in three dimensions by means of this method. In this work, results of experimental studies conducted on the effect of frequency on the analysis of the concrete by USWT are explained. The test device used in experimental studies has 24 transducers and its operating frequency range is 25-250 kHz. 50x50x22 cm sized three concrete specimens were produced in the laboratory for the experiments. Different materials were embedded in the concrete specimens to represent reinforcement and defects. Experiments were carried out at four different frequency values (25-50-100-200 kHz) on each specimen. The tomographic crosssections obtained at each frequency value were studied. The reinforcement and defects obtained in tomography sections were tried to match the known properties of placed objects in the concrete specimens. According to the results obtained in this study the accuracy of the results obtained depending on the frequency value varies according to the characteristics of the defect. The materials placed in the specimens tested at 25 kHz and 50 kHz values were determined with high accuracy whereas the values of 100 kHz and 200 kHz were only satisfactory to determine the specimen sizes, in other words, the boundaries of the concrete element. [ABSTRACT FROM AUTHOR]

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In this work, C20, C30 and C40 classification types of concrete where normal aggregate and barite were used as an aggregate have been produce in three different series. The physical properties, mechanical properties and radiation absorption coefficients of these produced concrete have been obtained. The variation of constituent of concrete and the rate of barite in aggregate as a function of strength and linear attenuation coefficients have been obtained by statistical analysis. It has been found that using barite instead of normal aggregate increased linear absorption coefficients and changed the physical and mechanical properties of concrete. [ABSTRACT FROM AUTHOR]

In this study, the effects of confined concrete models on behavior of reinforced concrete structures are investigated at member and system levels. The widely-accepted concrete models such as Modified Kent-Park. Mander, and Saatcioglu-Razvi are considered. A four- storey structure was designed and detailed according to 1975 Turkish Earthquake Code to reflect a typical example of building stock in Turkey. The building was considered to be in Earthquake Zone I and on Z3 Soil Type. Nonlinear behavior of the building frame was modeled by considering the inelastic section behaviour of each beam and column elements for different concrete class and transverse reinforcement spacing. The models were subjected to pushover analysis. The differences of confined concrete models were investigated for both reinforced concrete member and system levels. At the end of analyses, it was observed that although there were some differences at the section level, the effects of confined concrete models were negligible at the system level. [ABSTRACT FROM AUTHOR]