Title:
Proposed Revisions to the Strength Reduction Factor for Axially Loaded Members
Author(s):
Rémy D. Lequesne and José A. Pincheira
Publication:
Concrete International
Volume:
36
Issue:
9
Appears on pages(s):
43-49
Keywords:
column, wall, design, interaction diagram
DOI:
Date:
9/1/2014
Abstract:
Interaction diagrams computed for flanged sections according to ACI 318-11 provisions can result in unreasonable design strengths. In particular, the design interaction diagram can show, in some cases, increased axial load capacity with increased eccentricity at high axial loads. This anomaly is an unintended consequence of the changes to the definition of the strength reduction factor (?) adopted in 2002 and that remains in effect today. The article presents a modified ?-factor definition based on both net tensile strain and axial load. The proposed definition corrects the anomalous results in the design interaction diagram for flanged sections and has the same format as that of the 2011 Code.