topic Re: Slab Punching Calculation note in Robot Structural Analysis Forum

Slab Punching Calculation note

EY23 — Tue, 26 Aug 2025 07:02:51 GMT

Hello All,

Could anyone kindly explain the orientation of Mscx and Mscy in the punching results note?

I’ve attached some examples where you can see the differences in the results. From what I understand, Mscx corresponds to the moment about the local slab axis aligned with the column, and similarly for Mscy. However, the sign convention (+/–) is confusing.

I noticed that when the slab axis has the same orientation as the column axis, the result is positive, and vice versa. Nevertheless, if you compare Case 3 and Case 4, the applied moment behaves differently: in one case it is clockwise, while in the other it is counterclockwise.

Your help is much appreciated

Re: Slab Punching Calculation note

EY23 — Fri, 29 Aug 2025 12:13:29 GMT

Any Support?

Re: Slab Punching Calculation note

Simau — Mon, 01 Sep 2025 11:17:32 GMT

Hi @EY23

Could you Zip and share your model

Re: Slab Punching Calculation note

EY23 — Mon, 01 Sep 2025 17:44:56 GMT

Thank you for your reply. I have attached the model.

Re: Slab Punching Calculation note

Simau — Mon, 01 Sep 2025 20:26:33 GMT

Hi @EY23

When using Eurocode instead of ACI, moments are displaying without sign.

This is not the right place to analyse moments sign.

Use Maps instead, you'll see that columns local axis have no influence on panels moments sign

Re: Slab Punching Calculation note

Ira_Alexandrovsky — Thu, 18 Dec 2025 10:18:09 GMT

What does alpha mean in EC2?

Re: Slab Punching Calculation note

Simau — Thu, 18 Dec 2025 12:30:42 GMT

Alpha is the angle of the punching shear reinforcement with the plane of the slab.

Re: Slab Punching Calculation note

iat — Thu, 05 Mar 2026 16:54:12 GMT

??????