Determination of seismic performance of an existing reinforcedconcrete building by nonlinear calculation method and optimumstrengthening suggestions

Earthquakes occur when sudden fractures in the Earth's crust cause vibration waves, resulting in the shaking of the environment. Due to the unpredictable nature of earthquakes, it's crucial for existing structures always to be prepared. Turkey is in one of the most active earthquake belts globally, making it susceptible to destructive earthquakes. Notably, Turkey has faced several devastating earthquakes in the past. These include the August 17, 1999, Gölcük earthquake, the November 12, 1999, Düzce earthquake, the October 23, 2011, Van earthquake, and most recently, the February 6, 2023, Kahramanmaraş earthquakes. The Kahramanmaraş earthquakes, magnitudes of 7.8 and 7.5, occurred 9 hours apart in Pazarcık and Elbistan. They resulted in the loss of at least 53,537 lives and the destruction of 518,000 houses across 11 provinces. These earthquakes also had a significant economic impact. Given these consequences, it is essential to design and construct earthquakeresistant buildings and assess the earthquake performance of existing structures. The Regulation on Buildings to be Built in Earthquake Zones (DBYBHY) was introduced in 2007 to evaluate the earthquake performance of existing buildings, enabling their assessment and retrofitting. Subsequently, the Turkey Building Earthquake Regulation-2018 (TBDY-2018) further refined the concept of performance evaluation with a focus on design and assessment according to deformation. With modern regulations and advancements in the computer industry, it is now possible to determine the earthquake performance of existing structures. In Turkey, a country susceptible to earthquakes, it is crucial to evaluate the performance of existing structures under seismic effects. As part of this thesis, a 9-story reinforced concrete building in Şanlıurfa province was assessed according to TBDY 2018 using nonlinear analysis in the time domain. Retrofitting options were identified and implemented upon finding that the building did not meet the required performance level. Subsequent performance analysis confirmed that the building now met the level of performance needed. Finally, a cost analysis was conducted to determine the structure's most optimal and economical retrofitting option.