Verification of Buckling Analysis in Staad
Verification of Buckling Analysis in Staad
(OP)
Did anyone verify the buckling analysis in staad? I just tried a simple Example from "Steel Design" textbook, but theoretical Euler solution gives different results from that Staad does. The example is W12x50 beam, 20 ft long with two end pinned. Using Euler theory, the buckling load is 278.9 kips. Using Buckling Analysis in Staad, I got the buckling factor of 193 at the load case with 10 kips, which means the buckling capacity is 1930 kips. Why is there so much difference? Did I make any mistakes? Thanks!





RE: Verification of Buckling Analysis in Staad
Here are my results:
Theoretical: 279.8 kips
Advanced Solver, broke member into 10 segments: 285.8 kips
Basic Solver, 10 segments, 0.01 kip transverse load at center causing weak axis bending: 285.8 kips (Thank you very much.)
Within about 2% of theoretical. I thought I had got even closer results before doing a similar study but maybe I dream. A weird thing is I could have sworn I have done a single element before using the advanced solver successfully but when I tried it this time it crashed. I'm using release 20.07.05.15.
RE: Verification of Buckling Analysis in Staad
For English they use 29000 ksi, which is what I used to calc the theoretical. For metric they use 29732.7 ksi. Which is what it was using when I ran the problems. Why such a weird number you ask? That's 205000 MPa, which is not weird number.
Any who, when I plug this value of E in I get 286.8 kip critical load (theoretical). Only about 0.3% different, which is more what I'm used to seeing.
You just gotta love the guys at Bentley for laying these mines all over the country side. (I know, the guys at Bentley didn't do it, but they bought the guys who did.)
RE: Verification of Buckling Analysis in Staad
Bentley's documentation of STAAD is horrible.
Try sometime to find the list of issues "fixed" in each release.
RE: Verification of Buckling Analysis in Staad
It's nice to know what they have fixed, but I what I find troubling is they don't keep a running list of of current bugs on their website. Sometimes there are some rather serious bugs and I think they owe it to their customers to let them know.
Back to the O.P., forest00, were you able to get correct results now?
RE: Verification of Buckling Analysis in Staad