Table 4-2a Seismic Design Category Based on Short Period Response Accelerations
Value of SDS
Seismic Use Group
I
II
III
SDS < 0.167g
A
A
A
0.167g < SDS < 0.33g
B
B
C
0.33g < SDS < 0.50g
C
C
D
Da
Da
Da
0.50g < SDS
a
See footnote on Table 4-2b.
Table 4-2b Seismic Design Category Based on 1 Second Period Response Accelerations
Value of SDI
Seismic Use Group
I
II
III
SDI < 0.067g
A
A
A
0.067g < SDI < 0.133g
B
B
C
0.133g < SDI < 0.20g
C
C
D
Da
Da
Da
0.20g < SDI
a
Seismic Use Group I and II structures located on sites with mapped maximum considered earthquake spectral response acceleration at 1 second
period, S1, equal to or greater than 0.75g shall be assigned to Seismic Design Category E and Seismic Use Group III structures located on such
sites shall be assigned to Seismic Design Category F.
4-6
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