Vertical Shear Contour Plot in RAM Concept

I would normally recommend plotting Slab - Shear - (Mid depth) Max (and Min) for this, though you will get a warning like this for any Rule Set:

---------------------------Slab Plot Accuracy---------------------------

The selected slab plot may contain errors due to the max/min force enveloping being performed based on values about the x- and y- axes.

So I would usually recommend doing this for each single form load combination.

Keep in mind, instantaneous though shear is not something the program designs for. It designs for vertical one-way shear on sections (including strips) and punching shear on columns only.

Hi Seth,

Could you define what is defined by Slab - Shear -(Mid-Depth) X/Y?

Thanks,
Sam

Let's try an example. The top is a slab spanning between two walls, essentially a pure one-way behavior. The bottom is a slab on four columns, but with a wide aspect ratio, mostly two-way behavior. 

Here's a plot of the Shear in the X axis context along with a couple of slices:

Notice for the top slab that there is a nearly linear change from left to right with 0 shear at mid-span like you would see for a beam in classical theory. Furthermore, any horizontal slice would show basically the same results. The bottom slab at the columns has a similar lok, but the shear spikes near the point support. This is one of the key reasons why designers always integrate results across some width when designing concrete structures. To design for the point stresses would be overkill. 

Here's a plot of the Shear in the Y context:

Notice that there is very small, almost 0, shears for the one-way slab panning left right. The two-way slab still shows shear near the columns.

Finally, here the Max axis context which is a combination of the X and Y results.