I just joined a new firm and am checking a CONCEPT model. The design strip modeling is not as clean as I would have modeled it, but I'm trying not to have to redo everything and just to focus on certain areas. I have these shear reinforcing bars around the perimeter at slab depression locations. The CS trimming is (by default) off. When I change these strips to Max Shear Core, The shear reinforcing bars disappear, but now there are now (3) #6 bottom bars being added at those locations.
Here's my thinking:
I think that using max shear core for the L-shaped section will trim the top off and give me more shear core cross-sectional area than with no trimming, which means I get more concrete shear capacity and don't need additional shear reinforcing.
What I don't understand is how cross-section trimming is related to flexural stresses. When I check the service level slab bottom stresses at the flexural bar locations, they are higher with the max shear core trimming than with the no trimming option, but I was under the impression that trimming was only related to one way punching check of the shear cores. I have a screen shot of the locations that are in question and uploaded my model. The red circles are related to this question.
The blue circles are also an issue that I haven't been able to figure out and is a bit of a bonus question. At some iteration of this slab model, jacks were added in the middle of the slab and, since then these two bottom bars (circled in blue) appeared. Is there a reason that these should suddenly show up?