Determining the dynamic characteristic of a strengthened rc structure with operational modal analysis technique

In this thesis study, the Operational Modal Analysis Method, also known as environmental vibration testing, was used to determine the dynamic characteristics of a reinforced concrete structure undergoing strengthening operations. One of the main reasons for selecting this method in the study is that it does not require a known effect or, in other words, an excitation force during its application. Instead of excitation forces, the Operational Modal Analysis Method utilizes environmental effects such as traffic, pedestrian movements, noise, etc. Due to the complexity and difficulty of exciting multi-story or complex structures using excitation forces, the Operational Modal Analysis Method is frequently preferred in such structures. Furthermore, this method does not necessitate long-term closure of structures during its application, thus avoiding disruptions in daily life. This significantly enhances the feasibility of the method. Prior to the strengthening operations of the reinforced concrete structure used in this study, a three-dimensional finite element model was created according to its design, assuming that the walls were not demolished or removed. The dynamic characteristics of the structure were obtained by applying theoretical modal analysis using the SAP2000 program on the created three-dimensional finite element model. Subsequently, the dynamic characteristics were experimentally obtained using the Operational Modal Analysis Method and compared with the results obtained from the theoretical analysis. The finite element model was improved using the method of changing the elastic modulus. The same procedures were repeated after the demolition and removal of the walls. As a result of the study, it was determined that the use of the Operational Modal Analysis Method before and after the demolition and removal of walls in reinforced concrete structures undergoing strengthening operations is necessary and important for improving the finite element models of the structures.