RAM Elements - Torsion Design

I'm having some issues with torsional design in RAM Elements. I have a column that is fixed on top and bottom with a torsional moment applied at a point near midheight of the column. After analysis I am able to see the torsional moment showing up in the "member forces" diagram.

I've run several scenarios and am having issues that will be described below:

  • Running with an HSS member and clicking the "include torsional design" checkbox
    • Analysis runs fine but stress ratio shows up as "NAN" (presumably "not a number").
    • Looking into the design report, I see the value of NAN for both the demand as well as the DG9 EQ 4.13 check.
  • Running with an HSS member and NOT clicking the "include torsional design" checkbox
    • Analysis runs fine and stress ratio shows up as 0.00.
    • Looking into the design report, I see a D/C ratio of 9.4 as my demand is much higher than my capacity. As noted before though, this is not reflected in the overall status or the stress ratio. You need to actually go into the design report which is troubling.
  • Running with an WF member and clicking the "include torsional design" checkbox.
    • Analysis runs fine and stress ratio shows up as a number greater than zero.
    • Looking into the design report, torsion is included correctly using DG9.
  • Running with an WF member and NOT clicking the "include torsional design" checkbox
    • Analysis runs fine and stress ratio shows up as 0.00.
    • Looking into the design report, torsion is not included as a check.

So basically for my case, the program appears to be doing what is intended for a WF shape but not an HSS shape. With teh WF shape, we either check torsion w/ DG9 or we ignore it, depending on the checkbox. For the HSS section (which I believe used to design for torsion before the checkbox was even an option), it appears we are not necessarily correct in either case. We either return "NAN" or we check torsion but do not report its effects.

Might be missing something here so let me know what you think!

Parents Reply Children