Abstract:

The TBDY-2019 regulations for the accounting and design of concrete structures have made extensive changes. With the new earthquake regulation in force in January 2019, the use of this regulation in the designs of new buildings has now become mandatory. One of the changes made together with the new regulations is the calculation of the natural vibration period of the structures. The TBDY-2019 regulations suggest that an empirical formula may be used under certain conditions. This new formula (T=Ct*HN 3/4) not included in the TDY-2007 regulation will now be available to replace the Rayleigh period account if the requirements required in the regulation are fulfilled. It is important to review whether this recommended formula is applicable for the construction period, which is very important in the calculation of the earthquake load of buildings. For this purpose, the Rayleigh period formula is compared analytically with the empirical formula given in the regulations in this study. In this comparison made using the ETABS building analysis program, 2-5-storey concrete frame + roof-type housing and school building were considered according to different floor classes. In the analyses made, the base cutting force from the Rayleigh period in the ZA ground class for housing and school structure is approximately 20% to 25% greater than the base cutting force from the empirical formula in BYS7, while 8.5% greater in BYS8. Compared to BYS6, the base cutting force from the empirical formula increased by 7 to 19 percent due to the increase in the floor height from the base cutting force from Rayleigh. In this case, the empirical formula suggested by the regulation with the idea of staying on the safe side only gives a higher base cutting force than Rayleigh for the BYS6 condition. Therefore, it is recommended that the empirical formula recommended for BYS6, BYS7 and BYS8 be re-evaluated and the need for a comprehensive evaluation by conducting analyses through different structural models.

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