Seismic Evaluation of RC Building Designed by 1975 Turkish Seismic Code (A Case Study)

Abstract

This study evaluates the seismic performance of a five-story reinforced concrete building located in Samsun, designed according to the 1975 Earthquake Code, using the principles of TBDY 2018. The structure was modeled using the ETABS analysis program, and an incremental pushover analysis was applied. The effects of different stirrup arrangements and hook angles on structural performance were investigated. The analysis results indicate that confining the end regions of columns and using 135° hook angles significantly improved the damage levels of the columns. Model D demonstrated the best performance, minimizing plastic hinge formation and achieving the highest ductility at target displacement levels. In contrast, Model A, which lacked confinement and used 90° hooks, exhibited weaker performance. The target displacement values were determined as 57.286 mm in the X-direction and 30.838 mm in the Y-direction. The obtained capacity curves and plastic hinge distributions clearly illustrate the seismic performance of the building under various scenarios. The results emphasize the critical importance of adhering to design principles specified in earthquake codes to ensure structural resilience. Additionally, it was observed that the building, constructed in 1995 based on the 1975 Earthquake Code, did not exhibit collapse or advanced damage levels when analyzed under TBDY 2018 standards. This highlights the necessity of accurately defining material properties and detailing in compliance with regulatory requirements during the design phase to ensure seismic resilience. Future studies can focus on time-history analyses, the effects of material variations, and retrofitting techniques for older structures to further deepen the findings.