ACI 10.12.3.2 min moment M2--what is the reason?

[hippo11]

=Pu(0.6+0.03h)

What is the reason for this min moment? Pls don't tell me "because it's in the code".... Is it for construction errors, etc? What's the theory/background behind this? I couldn't find anything in the commentary.

And if you do a P-bigdelta + P-littledelta analysis in ETABS, can I ignore this min moment? Thx

 

[civilperson]

Due to increase curvature of the column from creep.

 

[csd72]

This is a minimum eccentricity, to allow for eccentric application of loads, out of straightness e.t.c.

If the moment is zero, then Pdelta makes no difference as it is multiplying moments.

You need to remember that all structures have construction tolerances and are never built perfect.