26.7 : 偏心荷重下の柱の設計

For a column loaded with an eccentric axial load in the plane of symmetry, the normal stresses due to eccentric load can be written as stresses due to an equivalent centric load and bending.

While designing columns with eccentric loadings, the maximum stress developed in the column shall not exceed the maximum allowable stress. This condition can be satisfied using two distinct approaches.

The allowable stress method assumes that the allowable stress for the eccentrically loaded column is the same as the maximum stress for the centrally loaded column. The allowable stress for the column can be expressed as a function of the slenderness ratio.

The allowable stress for centric loading is smaller than the one due to the bending moment. This results in the allowable stress method being overly conservative. 

On the other hand, the interaction method considers the allowable stress due to centric loading and bending into account.

It provides an equation for the maximum stress under centric loading when there's no couple moment. Similarly, it defines the maximum stress from pure bending when there's no loading.