Design and Cost Comparison of Reinforced Concrete Structures Modeled according to TBDY 2018 in terms of Earthquake Soil Motion

Our country is located in an active seismic zone and has therefore been subjected to large-scale earthquakes with a long historical record. Significant past earthquakes have resulted in fatalities and structural damage. For instance, events such as the 1939 Erzincan Earthquake, the 1943 Samsun Earthquake, and the 1999 Kocaeli Earthquake have deeply affected the country. However, the two earthquakes on February 6, 2023, have been recorded as the largest earthquakes in the last century. These earthquakes occurred on the East Anatolian Fault and directly affected 11 cities. In terms of loss of life and property, they caused three times more damage than the 1999 Marmara Earthquake. Reinforced concrete structures in our country are constructed according to specific standards. The construction criteria for buildings in seismic zones are determined by regulations. The regulation that came into effect in 2018 includes classifications based on earthquake levels. These classifications range from Earthquake Soil Motion Level-1 (DD-1) to Earthquake Soil Motion Level-4 (DD-4). In the design of reinforced concrete structures, the DD-2 Soil motion, which has a 10% probability of occurrence in 50 years, is considered as the minimum criterion. However, in this study, a reinforced concrete structure to be built in the Sakarya province will be modeled according to both DD-1 and DD-2 levels. The differences between these two approaches will be examined, and the losses and additional costs that would arise if DD-1 is considered in the design will be evaluated. The results will be analyzed and interpreted comprehensively. This study aims to shed light on the decision-making process in the design of structures in earthquake-prone regions.