Our office usually uses RAM to design composite floors, but for a new project, we're trying to use this extension. I have run into a few issues, however, that have caused me to question the quality of the product and the validity of results. If anyone can provide explanations for these things, it would be much appreciated.
For reference I have attached printouts of the reports for the same beam with the same design--the first was designed by this extension. The second was created in the same way, and then the number of studs was changed by 3 before immediately being changed back to the program-created design (13). None of the design options were modified at all between the two designs.
In looking at the report, several things are strange under "Design Settings" even before we get into the numbers:
- "Percent to Camber" is shown in feet and inches (?), and I cannot find any relation of this number to the ratio provided in the "Composite settings" dialog (0.8).
- "Stud Height" is shown as 192/256" (no option is available to change this in the "Composite settings" dialog, and the program obviously did not actually use a height of 192/256" for design because this would be below the deck height)
- "Stud Step" is 0'-5". I can find no description of what this means other than the slightly longer description next to it, "Stud count step." Why does a count have dimensions in feet and inches? And this obviously is not the interval by which the stud count is increased to find a working design because the number of studs provided by the program was 13. Maybe this is actually the stud height? Then what is the other number describing?
Next, the results.
In the program-created design, there are 7 checks, with the controlling ratio provided at the end. In the modified-and-then-changed-back design, there are 10 checks--the additional checks are for "Stud Spacing", "Percent Composite", and "Stud Capacity". Why weren't these checks shown before? And what does "Stud Capacity" refer to? The failure mode of stud failure should be included in the "Composite Strength" check, right?
Looking at the numbers:
In the first design, the composite deflection ratio is given as 0.73. This can be checked against the deflection in the "NetTotal" case (243/256") for the 26'-0" span for which L/240 = 1.3". So 0.73 is correct. BUT, for the other design, (which, you remember, should be exactly the same), the ratio is given as 0.77, while the "NetTotal" deflection is unchanged.
Is anyone with experience with this extension able to give an explanation for these things?