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Horizontal elastic design spectral accelerations SaSa, which are the coordinates of the horizontal elastic design spectrum for any considered earthquake ground motion level, are defined in terms of gravity [g] depending on the natural vibration period.
With the spectral response acceleration parameters obtained from USGS depending on the coordinates, horizontal elastic design spectrum Sa isdetermined according to the formula below. It is represented by a total of 4 functions, different in each region. It’s shown in the graph below.
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It’s calculated determined with the equation 11.4-5 from T=0 to T0 .
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It’s equal SDS from T0 to Ts .
It’s calculated determined with the equation 11.4-6 from Ts to TL .
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It’s calculated determined with the equation 11.4-7 for periods greater than TL.
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