Section E1/Compression Member Design
AISC 360-22 Chapter E covers axial compression member (column) design including slenderness, buckling modes, and nominal strength.
The nominal compressive strength is determined based on the limit state of flexural buckling. The critical stress (Fcr) depends on the slenderness ratio (KL/r) relative to the column's elastic buckling stress. For slender columns (high KL/r), elastic buckling controls. For stocky columns (low KL/r), inelastic buckling or yielding controls. The effective length factor K accounts for end restraint conditions. The maximum slenderness ratio KL/r should preferably not exceed 200 for columns.
Why this section exists
Columns carry compressive loads from the building above to the foundations below. Unlike tension members that simply yield, compression members can buckle, which is a sudden lateral displacement that causes catastrophic failure at loads well below the material yield strength. The column design equations account for this instability and ensure that columns are sized to resist buckling under the design loads.
What plan reviewers look for
Plan reviewers check that column sizes shown on the framing plans are consistent with the structural calculations. They verify the unbraced length and effective length factor (K) used in the design, especially for columns in moment frames where K exceeds 1.0. They check that column splices and base plates are detailed to transfer the design forces.
Common violations
Related AISC 360 requirements
Chapter F covers flexural (beam) member design. Chapter H covers combined axial and bending (beam-column interaction). Section J4.1covers the strength of connected elements at column base plates and splices.