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
Do you happen to know how Gamma Vx and Vy are applied? Looking at a column, oriented with S north and R east, the Gamma Vx is applied to the face perpendicular to the x-axis correct? And would thus be used in the calculation for steel at the column along the x-axis (bending about y).
Gamma Vx and Vy are defined relative to principal axis of the punching check. Those may or may not be aligned with the local axes of the column. Gamma Vx is associated with unbalanced moment about the x principal axis of the punch section. Gamma Vy is associated with the unbalanced moment about the y axis. If the principal axis is aligned with the local column axes, the principal x axis would be aligned with the local R axis of the column.