In viewing the forces in walls and slabs using contours, it is of great help to look at the lower left portion of the screen which shows the maximum and minimum value of forces/stresses. This is particularly helpful if you’re evaluating the areas that crack under tensile loading which are usually caused by lateral loads.
And just in case you are trying to pinpoint the exact location of that force, you have to set the Contour Averaging at Nodes to “None” to identify that specific panel. Because if you set Contour Averaging at Nodes by “By Objects” you will not see graphically where the maximum force/stress occurs. And the reason is because ETABS is averaging the forces/stresses to adjacent panels.
Say for example you’re threshold is 1200 kN and you saw a value of say 1500 kN, don’t panic, yet. That value might just be occurring on a certain panel. After all the real life wall isn’t really made up of separate panels and so averaging is completely justified.
As an example, please refer to the succeeding photos as I emphasize some points.
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source https://www.civilax.com/a-note-regarding-shell-force-stress-contours-in-etabs/