I tried the benchmark problem, case 1, shown in AISC 13th edition, page 16.1-435 in STAAD(X). I was unable to get the correct answer. I used P-Delta analysis with P-large delta and P-small delta. I've done the same problem in STAAD.Pro and got the correct answer. Has anybody been successful at running the benchmark problem? Don't forget for your test case Mmax/Mo and ymax/yo should be greater than 2.5.
No takers? Maybe this will get the ball rolling. Here's my STAAD(X) file and my calc. Hmm . . . it doesn't like the "stdx" extension. Oh well, I changed it to "txt". You'll have to change it back to "stdx".
I thought there would be more interest in this since it's critical that the program be able to do this in order to use the direct analysis method, unless you insert additional nodes along the member. Is anyone using STAAD(X) for actual production work yet? If so, how are you addressing this issue?