Beton elasatisite modülünün ultrasonik ses dalgası yayılma hızı ile tahmin edilmesi

Since seismicity is active in Turkey, most of the buildings are vulnerable against earthquake excitation. So, inspections of buildings are vital. Concrete is one of the most important parameter effect the performance of the building. Obtaining mechanical properties of concrete is also one of the most challenges in inspection of the building. Obtaining elastic modulus of concrete is also one of the most challenging since it requires sophisticated measuring system. Classical technique which require taking a piece of concrete for compression testing causes more labor, time and costs. So a simple method required especially in case of quick inspection of the building. Ultrasonic pulse velocity is one of the well known techniques for a nun destructive evaluation of concrete. The technique is easy, fast and requires less labor. However it is not reliably by itself. In order to increase the reliability, match curve must be prepared for every different concrete type. So, this study intended to develop a model for concrete used especially in Diyarbakir district. This study both includes experimental and empirical work. In the experimental part eleven cylinder specimens were produced from concrete work of different stories of a building being retrofitted in Diyarbakir. Dimension of cylinders are 150 mm in diameter and 300 mm in height. All the specimens were cured 28 days in water and tested after at least 28 days. Ultrasonic pulse velocity (UPV) tests were carried out at first. For each specimen UPV tests were carried out at five different points and UPV values for each specimen was evaluated as average of these five values. After UPV tests compression tests were carried out for all specimen. For compression tests, monotonically axial load was increased until failure and the load and deformation values were noted for each load increment. After all the UPV and compression tests were carried obtained data were used for developing a model to predict elastic modulus of concrete from UPV values. In model developing regression analysis was utilized. Data analyzed to obtained reasonable relation between UPV and elastic modulus. As a result an equation was developed (Equation 1). As seen in Equation 1 only UPV values required to predict elastic modulus of inspected concrete. Ec=46.311×UPV-169.77 (1) In these equations UPV and Ec values must be in km/s and GPa units, respectively. The last part of this study is the performances evaluation of constructed model. To check prediction performance of the model a bunch of data was collected from literature. All of our data was not used in the performance evaluation to make an objective evaluation. Totally 19 data was used in performance evaluation. All the data are of normal concrete and of cylinder specimens. To reach a comment for necessity of our equations, a comparison was made between our equations and few equations from literature. Statistical parameters such as average and relative error were used in performance check. For the best model average of predicted and experimental compressive strength should be nearest one and relative error should smallest. Statistical evaluation parameters for all models are given as follow,The above table clearly showed that relative error is smallest and Average is closest to one for Equation 1. So, we can conclude that for the data grope was used, equation 1 is the best in prediction of the elastic modulus from UPV.