For further information on the Seismic Wizard see the example below and ASCE 7 Wind and Seismic Load Combinations.
Importance Factor IP = 1
Component Response Modification Factor RP = 3.5, from Table 13.6-1, "Piping in accordance with ASME B31,"
Mapped MCE Spectral Response Acceleration Ss = 1.552, Mapped MCE Spectral Response Acceleration at short periods according to Section 11.4.1.
Site Coefficient (Fa) = 1.0 for Site Class D, according to Table 11.4-1.
Maximum Considered Earthquake MCE SMS - The MCE is adjusted for site class effects as defined in Section 11.4.3,
SMS = Fa SS = 1.552
SDS - Design elastic response acceleration at short period (0.2 sec), from Section 11.4.4.
SDS= 2/3 SMS = 2/3 * 1.552 = 1.0347
The appropriate seismic acceleration is aH
= [ (0.4aPSDS) / ( RP / IP )] ( 1 + 2z/h)
= [(0.4 x 2.5 x 1.0347)/(3.5/1.0)](1 + 2 * 0.5)
= 0.59126
Check limits on aH:
aH <= 1.6 * SDS* IP = 1.6 * 1.0347 * 1.0 = 1.65552
aH >= 0.3 * SDS * IP = 0.3 * 1.0347 * 1.0 = 0.31041
aH = 0.31041
aH = 0.2 SDS= 0.2 * 1.0347 = 0.20694,
Section 13.1.7 states, "The earthquake loads determined in accordance with Section 13.3.1 shall be multiplied by a factor of 0.7."
aH = 0.7 * 0.31041 = 0.2173
av = 0.7 * 0.20694 = 0.1149
CAESAR II displays the calculated gravity factor on the Uniform Loads tab.