I have modelled a rectangular concrete tank in STAAD using plate elements and need to do some additional calculations to check the crack widths do not exceed a given value.
I can get a contour plot of the bending moments in the walls but when the tank is full and there is no backfill to it, there will also be a tensile force in the walls. Can I do a contour plot showing this tension?
I thought plotting SX or SY would give the tensile stress, and if I multiplied this by the section thickness it would give a force in kN/m. Doing this gives a tension of around 750 kN/m in one of the walls, whereas a design based on PCA guidance says it should be about 200 kN/m.