Performance evaluation of an existing reinforced concrete building by using different strengthening methods

Seismic performance assessments of existing public-type buildings are conducted to determine whether these structures can meet the targeted performance levels under possible earthquake scenarios. In particular, for buildings that are required to remain operational immediately after an earthquake such as hospitals, dormitories, schools, and administrative facilities, the performance levels are generally set as Limited Damage or Controlled Damage in accordance with the provisions of the Turkish Building Earthquake Code. In these studies, the current condition of the building is first identified through on-site reinforcement surveys, concrete strength measurements, examination of design documents, and structural modeling. Subsequently, the seismic behavior of the building is simulated using either linear or nonlinear analysis methods. The results obtained are then evaluated in terms of interstory drift, section damage states, and plastic hinge formations, thereby revealing whether the structure, in its existing state, satisfies the intended performance objectives. In cases where the performance is found to be inadequate, appropriate strengthening methods are proposed. In this thesis study, the seismic performance of an existing reinforced concrete dormitory-type building was investigated using the nonlinear static pushover analysis method. After identifying the damage states of the structural system elements in the existing building, its seismic performance was evaluated. Since the building failed to meet the expected performance levels for both earthquake hazard levels (DD1 – Controlled Damage and DD3 – Limited Damage), the need for strengthening became evident. As an initial step, Fiber Reinforced Polymer was applied to increase the shear and ductility capacities of brittle structural elements. Subsequently, classical strengthening methods such as column jacketing and the addition of reinforced concrete shear walls were employed with the aim of enhancing the building's seismic performance. In this approach, particular attention was paid to architectural requirements and to preventing the introduction of additional torsional irregularities in the structure. To ensure the structural safety of the existing reinforced concrete building, nonlinear analyses were conducted in both directions for the two different strengthening methods applied. The resulting capacity curves were presented in a comparative manner. The damage states and performance levels observed in both the existing and strengthened buildings were presented in detail. In the final stage of the thesis, a cost analysis of the strengthened buildings was carried out, and a comparison was made based on total costs. Through this cost evaluation, the conclusions and recommendations section provides insights regarding which strengthening method would be more advantageous for the existing building Keywords: Seismic Performance, Nonlinear Analysis, Strengthening Method, Damage States, Existing Reinforced Concrete Building