Biaxial Column Bending

Certainly, the program can check columns in bi-axial bending. Are you thinking about Steel or Concrete columns? What design code?

Hi Seth, I've completed some column designs in Staad using the design sub-tab under the modelling tab. I have observed that when I request a detailed output the design chart shown is a 2D interaction diagram, however a 3D interaction is required for designing Bi-axial columns. This leads me to believe that the columns are only designed for the maximum moment from one direction, rather than a combination of the worst case from both lateral axes.

STAAD.Pro does design columns for axial + bi-axial moments. Based on the axial load and the arrangement of bars within the cross section it first comes up with the uniaxial moment capacities independently about each axis ( represented by the terms Mycap and Mzcap in the equations below) . Subsequently it solves for the interaction equation as shown next

These steps are outlined in the help documentation. For example to find out the details on how column design is carried out as per the ACI code, you may refer to the section of the software help ( Help > Contents ) as marked below