## 5 Results and Discussion
Five of the eight provinces which use the same design spectrum are sufficient, while the others are insufficient, according to TSDC-2007. This finding shows that the updates will yield more realistic displacement demands for the structures. The same target displacements were obtained for these eight provinces located in the same earthquake hazard zone in the previous regulation. However, the values obtained through the updated regulation are different for all of these provinces. This reveals the necessity of a site-specific design spectrum instead of a regional-based design spectrum used in TSDC-2007. Structural analyses were carried out for two different stories (three-story and six-story). Only the site-specific design spectrum was considered as a variable for both stories. A complete agreement was achieved between all results obtained from both stories for different provinces. The natural vibration period has the same value in all structural models for both stories since the structural characteristic do not change in all provinces. The displacement values calculated on the idealized curve are close to each other. Additionally, seismic capacities obtained for different stories for different provinces have very close values to each other. The elastic stiffness value of the structure increases when the number of stories increases. Moreover, the elastic stiffness values obtained for different provinces take constant values in both stories. The most crucial difference in the structural analysis was obtained in the target displacements. The expected target displacement from the building decreases when the number of stories decreases. Displacement values increase when the design spectrum increases according to higher PGA values. This means that the building's expected earthquake movement capability is higher due to the higher values of the PGA. Structural analyses were also performed for the design spectra foreseen in the previous code. The same values were obtained for different story numbers in the same earthquake zone. In the previous code, calculations were made on a regional basis, and the concept of earthquake zones was expressed only for ground motion level with a repetition period of 475 years. Thus, Bilecik Bursa, Canakkale, Istanbul, Kocaeli, Sakarya, Tekirdag, and Yalova were considered as the first-degree earthquake hazard regions, while Edirne and Kirklareli were the fourth-degree earthquake regions. The effective ground acceleration coefficient for first-degree regions was 0.40 g, while it was 0.10 g for fourth-degree regions. However, PGA values were calculated as 0.36 to 1.12 g for the probability of exceedance 2%; 0.16 to 0.67 g for 10% probability of exceedance; 0.06 to 0.27 g for 50% probability of exceedance; and 0.04 to 0.14 g for 68% probability of exceedance in 50 years for provincial centers according to the updated earthquake hazard map. It was determined that the highest value obtained due to the ground motion level predicted by the previous regulation increased with the new regulation. Earthquake parameters were calculated for all provinces, and horizontal and vertical design spectrum curves were obtained for each province center, and comparisons were made. Although the local soil conditions and earthquake ground motion level are constant values, we determined that earthquake parameters significantly differ from each other. The seismicity elements of the region, such as fault/fault groups and their characteristics, the distance from the determined geographical locations to fault/fault groups, and the region's earthquake history are most likely the reason for these differences. We conclude that obtaining the design spectrum by considering the site-specific earthquake hazard estimations in the new earthquake regulations is a significant gain. This demonstrates the importance of the site-specific design spectrum that was missing in the previous regulations.