As 1170.4 Commentary Jun 2026

: The standard (supported by the commentary) scales requirements based on Earthquake Design Categories (EDC) , ranging from simple static analysis for EDC I to full dynamic analysis for EDC III.

Which are you dealing with?

: Guides engineers in establishing a clear "strength hierarchy" within a structure, which is vital for seismic assessments of existing buildings. Critical Updates & Observations as 1170.4 commentary

The commentary warns that AS 3600’s "seismic provisions" (Clause 11) are only triggered when the AS 1170.4 ductility requirement exceeds a threshold. It tells you exactly how to check this. : The standard (supported by the commentary) scales

: Offers detailed background on how to handle torsion in buildings, though recent reviews suggest some areas still require careful interpretation by designers. Critical Updates & Observations The commentary warns that

The core of the standard lies in the calculation of the horizontal equivalent static shear force ($V$). This is the base shear that the building must be designed to withstand.