Column Moment 2nd Order Effects Check

AMOST

Does S-Concrete (V2022.3) check if the ultimate moment Mu including second-order effects exceeds 1.4Mu due to first-order effects for slender columns, per sec. 6.2.5.3 of ACI 318-19? I'm unable to find it in the program documentation.

Matthew_Sauer1

Hello AMOST,

Thank you for your email. S-CONCRETE does not perform this check as described in your question.

In the ACI 318-19 code, clause 6.2.5.3, there is an identification of a main member, a 'column', and its restraining beams and other supporting members. Digging deeper into the commentary part of this clause, it is evident that the 1.4 factor is tied to systems of members, rather than single members within those systems.

S-CONCRETE itself is a section design solution that looks at elements in isolation, and for this reason users would be required to evaluate the magnification factor separately, and it would not be included in S-CONCRETE's calculations, or reports.

We hope this clears things up.

Regards,
Matthew Sauer

Altair Support

AMOST

Hello Matthew,

Thank you for your reply. I understand that the 2022 version does not make that check. However, I would like to quote part of the reply I received from Altair Support when I raised a case (CS0722893) at the same time I asked the community; "These implementations are part of the most recent builds of S-CONCRETE, most likely implementing the clause you referred to. We'll continue our investigation and get back to you once we have more information". (Alejandro Lopez). I have not received any further replies from them.

Regards

Matthew_Sauer1

Thanks, AMOST.

I'm aware of some changes to the language in the ACI 318-25 code related to this topic. At this stage, I'm afraid I don't have enough information to comment on specifics, but we will certainly update you if S-CONCRETE handles things differently in future codes, but I would not expect any changes to the ACI 318-19 on this topic.

Regards,
Matthew Sauer

Altair Support