The effect of concrete compressive strength on structural dynamic behavior in reinforced concrete structures

Dynamic load means a load whose size varies over time. It can also be defined as the load (force) that suddenly affects the structure and changes greatly in a short time. In addition to static forces, dynamic forces also have a very important place in structures. In fact, it is known that when the responses against static and dynamic loads are compared, the responses to dynamic forces are found to be higher. Earthquake forces are the most impactful of dynamic forces. Earthquake force creates horizontal movements. The importance of earthquake force in buildings in our country and in the world is an undeniable fact. If the earthquake force is not taken into account in the project, especially reinforced concrete structures can be affected extremely negatively. For this reason, many researches are carried out on how to improve the effect of forces acting on structures in earthquake engineering. One of the experimental methods used in these studies is shaking table experiments. As a result of the shaking table test, the capacity and dynamic characteristics of the structure under earthquake force are determined. In this thesis study, the shaking of column samples with different concrete compressive strengths was carried out with the forced forces on the shaking table. In the study, 6 column samples with different concrete compressive strength were prepared with 1/3 scaling. The steel class and geometric dimensions of the reinforced concrete column samples were designed as the same. Filtering and analysis of the data obtained from these reinforced concrete column samples, which were subjected to forced vibration on the shaking table, were performed and FRF graphs were obtained, and their dynamic characteristics were determined. The effects of the classification of concrete, which is the most basic material of reinforced concrete elements, on frequency and damping rate under earthquake effect were determined. Comparisons between the samples were made and various conclusions were reached regarding the application and analysis. As a result of the experiment, it was seen that the frequency value increased by 8,08% and the damping ratio decreased by 30,98%, compared to the ratio of the sample with the highest compressive strength (SN-06) to the sample with the lowest (SN-01). It has been proven that concrete compressive strength and frequency are directly proportional and damping ratio is inversely proportional.