## 2 Method
### Seismic Performance Evaluation of the Sample RC Structural Model
Material grades for concrete and reinforcement are taken from the seismic design code (TBEC-2018) [62] currently used in Turkiye. The same size and reinforcements were used in all columns and beams. In the region affected by the 2023 Kahramanmaras earthquakes, medium-rise reinforced concrete buildings were widely preferred. The reference building was taken as 7-storey in order to represent such structures. The sample reinforced-concrete structural model was considered as a pure reinforced-concrete frame, especially considering the RC structures before 2000 in the earthquake region. Therefore, the reference model does not contain any reinforced concrete shear walls. After numerical modeling, structural analyses were performed by applying both vertical and horizontal loads. The 2D and 3D models of the building and the applied loads are illustrated in Figure 5.  
In all structural models, force-based plastic hinge frame elements (infrmFBPH) were selected for the columns and beams. These elements restrict plasticity to a specific length and simulate force-based flexibility in extension. To accurately represent the stress-strain distribution across the section, an appropriate number of fiber elements were utilized. For the chosen sections, a total of one hundred fiber elements were assigned. The plastic-hinge length (L\({}_{\rm P}\)/L) was determined to be 16.67%. The column boundary conditions were set to resemble those of a cantilever, resulting in a fully fixed base and a free top end. The structural characteristics of the RC structural model are shown in Table 2.  
Figure 5: The 2D and 3D structural models and applied load. Pushover analysis was applied to all structural models. Pushover analysis is a structural engineering method used to estimate the seismic performance of a building or structure under earthquake loading. It is a static, nonlinear procedure that involves applying increasing lateral forces (representing the effects of an earthquake) to a model of the structure until it reaches a target displacement or failure point. The analysis helps to assess how a structure will behave under seismic forces, identifying potential weak points and providing valuable insights into its vulnerability. Pushover analysis is particularly useful for evaluating buildings that are expected to perform nonlinearly during an earthquake, offering a more realistic picture of their behavior compared to linear analysis methods [63; 64; 65; 66; 67]. The study does not explicitly mention using a recorded accelerogram from the 2023 Kahramanmaras earthquakes. Instead, seismic forces were applied based on pushover analysis, which is a static, nonlinear procedure rather than a dynamic time-history analysis. One of the results obtained from numerical analysis for each structural model considered within the scope of the study is the target displacements. It is crucial to define target displacements for failure assessment when specific performance limits of structural components are reached in performance-based structural engineering [68; 69]. In the widely adopted Eurocode 8 (Part 3), target displacements are determined by considering limit states [61; 70; 71]. A detailed explanation of the limit states considered in the paper is provided in Table 3, where all results from the numerical analyses are also presented.