Eccentricity estmate from Pu alone

[lejam]

When a member is subjected to combined axial compression P and moment M, it is usually convenient to replace the axial load and moment with an equal load P applied at eccentricity
e=M/P. The two loadings are said to be statically equivalent.

Eccentricity of a column load is calculated from e=M/P. Supposed you don't know the moments but know the axial load in opposite sides of a given column. Say the axial load is 100 kn on left side and 300 kn on right side of the column. What would be the estimated eccentricity given the complete axial loads only? Is there a ballpark estimate?

 

[asixth]

For corner columns in rc structures my initial estimate is Pu (floor load only) * 0.015 * Span. For stiffer columns I may bump it up a little. Internal columns without a large unbalanced span would be a third of this. This has generally worked well for me for typical floor plates braced by rc lift and stair cores.