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LRFD Eq. 5.6.4.6-1
LRFD Eq. 5.11.4.1.4-1
LRFD Eq. 5.11.4.1.4-2
LRFD Eq. 5.11.4.1.4-3
ACI
ACI defines their zones to be aligned with the 2018 IBC. ACI uses Seismic Design Categories (SDC) and 318-19 breaks them into 3 distinct sections. Section one is SDC A&B, section two is SDC C, and section three is SDC D,E, & F.
PCI
PCI defines their zones to be more aligned with ACI 318-19 and the 2018 IBC. The equations are based on ductility considerations which, according to the PCI BDM, are more appropriate for use with prestress piles in seismic regions.
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