Spectral Response Acceleration Parameters.

Symbols

F_S = Local ground impact coefficient for the short-period region
F₁ = Local ground impact coefficient for a period of 1.0 seconds
S_DS = Short-period design spectral acceleration coefficient [dimensionless]
S_D1 = Design spectral acceleration coefficient for a period of 1.0 seconds [dimensionless]
S_S = Short period map spectral acceleration coefficient [dimensionless]
S₁ = Map spectral acceleration coefficient for a period of 1.0 seconds [dimensionless]

Dimensional map spectral acceleration coefficient , four different levels of earthquake ground motion for Earthquake Hazard Maps are defined under:  

(a)   Short period map spectral acceleration coefficient S _S

(b)  Map spectral acceleration coefficient S ₁ for a period of 1.0 seconds

The map spectral acceleration coefficients corresponding to the geometric mean of the earthquake effects in two horizontal directions perpendicular to each other are determined by the map spectral accelerations for 5% damping rate based on the reference ground condition for a given earthquake ground motion level [( V _{S 30} ) = 760 m / s] . They are defined as dimensionless coefficients divided by the acceleration of gravity . For this reason, the equation described below is used to determine the effect of local soil impact coefficients while calculating under different soil conditions.

The map spectral acceleration coefficients S _S and S ₁ are converted into the design spectral acceleration coefficients S _DS and S _D1 as follows :

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Wherein F _S and F ₁ are defined below the local ground effect coefficients of the shows.  

In the Analysis Settings Wizard - Design Spectrums tab, design acceleration coefficients are obtained with the map spectral acceleration coefficients obtained depending on the coordinate with online and offline options. If the online option is used, acceleration coefficients are obtained from the AFAD Earthquake Hazard Map. The acceleration coefficients calculated over the program infrastructure are obtained in the offline option. Both options give the same results.