Yüksek, B.Tuǧrul Erdem, R.T.Yilmaz, T.Şengel, H.S.2026-02-102026-02-1020252149-8024https://doi.org/10.20528/cjsmec.2025.04.004https://search.trdizin.gov.tr/en/yayin/detay/1366521/performance-investigation-of-a-mixed-slab-building-with-beam-and-ribbed-slabshttps://hdl.handle.net/20.500.13091/12993Over time deterioration in material properties, unauthorized modifications, or construction defects can negatively affect the seismic behavior of structural members. Therefore, the in-situ identification and performance analysis of reinforced concrete elements, carried out to ensure the safety of the existing building stock, have become a fundamental part of examining structural characteristics and developing disaster risk reduction strategies. In this study, the structural performance analysis of an existing reinforced concrete building with a mixed slab system was conducted by using the STA4CAD V13.1 software. For this purpose, nonlinear pushover analysis was performed for each seismic direction. As the existing reinforced concrete building did not satisfy the requirements for the single-mode method prescribed in TBDY (2018), a multi-mode pushover analysis was conducted for the structure. Based on the results of nonlinear multi-mode pushover analysis, the damage states of the structural members were determined, and the performance level of the structure was evaluated. The targeted performance level of controlled damage, as defined in the Turkish Building Earthquake Code-2018 TBEC (2018), could not be achieved for the analyzed residential-type reinforced concrete building. However, the collapse prevention performance level was determined due to the damage occurrence in the structural elements. © 2025 by the Authors.eninfo:eu-repo/semantics/openAccessEarthquakeExisting BuildingMixed SlabNon-Linear AnalysisStructural System SafetyArticle10.20528/cjsmec.2025.04.0042-s2.0-105026288563