Vertical Design Response Spectrum

Symbols

F _S = Local ground impact coefficient for the short-period region
F ₁ = 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]
S ₁ = map spectral acceleration coefficient for a period of 1.0 seconds [dimensionless]
T = Natural vibration period [s]
S _aeD (T) = Vertical elastic design spectral acceleration [g]
T _AD = Vertical elastic design acceleration spectrum corner period [s]
T _BD = Vertical elastic design acceleration spectrum corner period [s]
T _LD = Transition period to constant displacement region in vertical elastic design spectrum [s]

Vertical Earthquake Effects

Horizontal Design Response Spectrum

With the spectral acceleration coefficients obtained from AFAD depending on the coordinates, the vertical elastic design spectrum S _aeD (T) is calculated according to the formula below . For the vertical elastic design spectrum, it is represented by a total of 3 functions, different in each region, and shown in the graph below.

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T _AD and T _BD vertical spectrum vertex periods and T _LD period are given below .

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In the Analysis Settings Wizard - Design Spectrums tab, the vertical design spectrum is calculated and graphed using the design spectral acceleration coefficients determined with online and offline options depending on the coordinates.

For ZF type soil, the calculation is not made in the above way due to the need for site-specific analysis. The calculated reduced design acceleration spectrum needs to be imported as a .txt file.