In relation to a previous post, where I asked about ACI 318-11 provisions in Ch. 13, I was wondering if there were easy steps to extract the phiVc, Vu, and Mu values that would be required for the calculations associated with gammaf*Msc found in 13.5.3.3? Would these be present in the Punching Shear Audit tab? Does Concept automatically calculate the gamma*Msc moment that would be required to design the additional steel? I know it doesn't yet add this steel, however if it already calculates the factored moment it can expedite a design.
Also, in reviewing some of the Punching Shear Audits, I noticed that values of Mr and Ms appear to be 0 for columns located at the edges of slabs, while interior columns have values associated with them (this is found under the "Starting Design: Base Design Envelopes"). If there is documentation explaining what the program is doing, can that be linked?
Thanks!
Yes, you can find helpful information in the Punching Shear Audit. Fz in the Base Design Envelope section is Vu. Mr and Ms in the Base Design Envelope section is Msc about each axis. The Unreinforced Stress Ratio listed in the Auditor is phiVc. Gamma-Vx and Gamma-Vy are reported and can be used to calculate GammaF (see ACI 318-11 13.5.3.1).
Mr = Ms = 0 would occur when the column reaction is 0. Are the edges columns defined as pinned (Fixed Near unchecked in column properties) in your model?
Answer Verified By: Eric Feuge-Miller
Yes they are. Do they need to be modified for the program to provide the moments I need to design for?
If this is the case, this will result in a smaller SSR design too correct?
It appears that Concept applies the "Fixed Near" to lower Frame (RAM SS) columns and both "Fixed Near" and "Fixed Far" for upper Frame columns, while leaving those unchecked on gravity columns.
Unless you can detail the column connection to justify a pinned condition, you should consider changing the fixity to fully fixed so that moments are transferred to the column. RAM Concept will automatically account for moment due to eccentricity of the column reaction to the centroid of the punching section even if the column is pinned.