## 5 Results and Discussion  
Structural earthquake damages and advances in engineering technologies require constant updating of the rules of earthquake-resistant structural design and seismic hazard risk of the regions. There have been some updates in Turkey due to the significant losses of life and property caused by earthquakes. Both rules and seismic hazard maps were updated in 2018 in Turkey. In this study, earthquake-structural parameter variations were analyzed on a regional basis using the Turkish Earthquake Hazard Map (2018). The Marmara Region, including eleven provinces, is an excellent example due to its characteristics such as high seismicity, population, and industrial facilities density. PGA and PGV values were calculated for different probabilities of exceedance for each provincial center. According to the findings obtained in this study, the provinces of Kocaeli and Karklaveli are under the highest and lowest earthquake risks, respectively. With the new regulation, the concept of the earthquake zone is no longer used. The design spectrum was in use on a regional basis, and this spectrum was valid for all provinces within the same earthquake zone in the previous regulation. The same effective ground acceleration coefficient is used in the same earthquake zone for the design spectrum that given inTSDC-2007. This situation is especially changed in TBEC-2018 specific for each geographical location. The spectral acceleration coefficients are used instead of the effective ground acceleration coefficient in the updated regulation. The spectral acceleration coefficients vary according to the coordinate and proximity to the fault with the new regulation. In order to reveal the effect of local soil conditions more clearly, local soil impact coefficients (F\({}_{8}\) and F\({}_{1}\)) were included in TBEC-2018. Four different earthquake ground motion levels are taken into account with the TBEC-2018, while only one earthquake ground motion level was taken into account in theTSDC-2007. In addition, while only the horizontal elastic design spectrum was used in TSDC-2007, both horizontal and vertical elastic design spectra started to be used with TBEC-2018. Analyses were carried out using the same design spectrum curve for Bilecik, Bursa, Canakkale, Istanbul, Kocaeli, Sakarya, Tekirdag, and Yalova, which are in the first-degree earthquake hazard zone \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Province** & **Code** & **Number of Story** & **DL (m)** & **SD (m)** & **NC (m)** \\ \hline Bilecik Bursa, Canakkale Istanbul, & & 3-story & 0.038 & 0.049 & 0.102 \\ Kocaeli, Sakarya, Tekirdag, Yalova & & 6-story & 0.114 & 0.146 & 0.253 \\ \hline Bilecik & & 3-story & 0.022 & 0.029 & 0.050 \\  & & 6-story & 0.067 & 0.087 & 0.150 \\ Bursa & & 3-story & 0.034 & 0.043 & 0.087 \\ Canakkale & & 6-story & 0.101 & 0.129 & 0.224 \\  & & 3-story & 0.028 & 0.036 & 0.067 \\  & & 6-story & 0.085 & 0.109 & 0.189 \\ Istanbul & & 3-story & 0.038 & 0.049 & 0.102 \\  & TBEC-2018 & 6-story & 0.113 & 0.145 & 0.252 \\ Kocaeli & & 3-story & 0.067 & 0.096 & 0.194 \\  & & 6-story & 0.190 & 0.243 & 0.421 \\ Sakarya & & 3-story & 0.063 & 0.091 & 0.184 \\  & & 6-story & 0.182 & 0.234 & 0.405 \\ Tekirdag & & 3-story & 0.037 & 0.047 & 0.098 \\  & & 6-story & 0.111 & 0.142 & 0.246 \\ Yalova & & 3-story & 0.057 & 0.084 & 0.171 \\  & & 6-story & 0.171 & 0.219 & 0.379 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Comparison of target displacements for damage estimation according to previous and updated codes. in the previous regulation. Therefore, the obtained values take the same values for these provinces in the same earthquake hazard zone. It was determined that the values obtained separately for each province are quite different from the previous ones by using the site-specific design spectrum. Target displacements are lower than the values predicted in TSDC-2007 for Bilecik, Bursa, Canakkale, Istanbul, and Tekirdag. The values obtained for Kocaeli, Sakarya, and Yalova are higher than the values of TSDC-2007.