Spectral Response Acceleration Parameters and Design Spectral Acceleration Parameters per ASCE 7-16 with ideCAD

How does ideCAD define design spectral response acceleration parameters, according to ASCE 7-16?

Symbols

F_a = Short-Period Site Coefficient
F_v = Long-Period Site Coefficient for a period of 1.0 seconds
S_MS = Short-period design spectral response acceleration parameter [dimensionless]
S_M1 = Design spectral response acceleration parameter for a period of 1.0 seconds [dimensionless]
S_S = the mapped MCER spectral response acceleration parameter at short periods as determined in accordance with Section 11.4.2,
S₁ = the mapped MCER spectral response acceleration parameter at a period of 1 s as determined in accordance with Section 11.4.2
S_D1 = Design spectral response acceleration parameter for a period of 1.0 seconds
S_DS = Design earthquake spectral response acceleration parameters at short periods

Dimensional map spectral response acceleration parameters, risk-targeted maximum considered earthquake ground motion, for USA Earthquake Hazard Maps, are defined under:  

(a)   Short period map spectral response acceleration parameter S_S

(b)  Map spectral response acceleration parameter S₁ for a period of 1.0 seconds

The map spectral response acceleration parameters are determined by the map spectral response accelerations for 5% damping ratio. 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 site soil coefficients while calculating under different soil conditions.

The map spectral response acceleration parameters S_S and S₁ are turned into the design spectral response acceleration parameters S_MS and S_M1 with Eq. 11.4-1 and 11.4-2.

Wherein F_a and F_v, defined below, shows the local site coefficients.

Design earthquake spectral response acceleration parameters at short periods, S_DS, and at 1-s periods, S_D1, are determined from Eq. 11.4-3 and 11.4-4.