Slenderness Effects

Owned by Tony Sun
Jul 08, 2024
1 min read

None

Slenderness shall be permitted to be neglected per ACI 318-19 Section 6.2.5.

P-Delta Analysis

An elastic second order analysis is performed when slenderness effects are set to P-Delta. In this analysis, the deformed geometry of the column is included in the equilibrium equations so that the additional moments due to the deflected shape are included. Enabling P-Delta ensures we also capture these effects from the lateral loads on the column.

Moment Magnification

The moment magnifier concept is an approximate design procedure that account for slenderness effects. Moments calculated using a first-order frame analysis are multiplied by a moment magnifier.

The moment magnification design method requires the designer to differentiate between non-sway frames and sway frames. Please note that the moment magnification method for sway frames is not included in Eriksson Column. Instead, second-order analysis (P-Delta analysis) is utilized for this scenario.

The ‘k value’ used for the moment magnification calculation could vary along the length of column. In the program, the ‘k value’ is conservatively used as a single value.

 

 

 

 

Â