ETABS TO SAFE MODEL REACTION INCONSISTENCIES

[vvaccare]

Good morning everyone,

I am currently working on an ETABs model, and when transferring over to SAFE, the reactions for each load case have minor inconsistencies. Most roughly in the 4 to 6 kip range. This occurs for every load case (DEAD LOAD, SUPER IMPOSED DL, LL, WIND, ETC.). Does any one have any insight into why this may be occurring? Thank you in advance.

 

[JoshPlumSE]

I've seen this before with another software (RISA). I can't say for sure that the issue is the same, but maybe it is.

If the solution you run in ETABS matches the solution run to get your SAFE reactions, then the results should be identical right. So, what could be different:
1) 2nd order effects: Is a P-Delta analysis included in your ETABS run. Does it match the way P-Delta is considered when the program produces the SAFE reactions?
2) non-linear elements: Do you have any tension only or compression only elements or such in your model? If so, how are these treated when the SAFE reactions are calculated?
3) Stiffness adjustments for Direct Analysis Method or concrete cracking or such. If these are handled differently between the two analyses, then the reactions would probably be different.

 

[sticksandtriangles]

Is this a model where you are replacing existing reactions with new reactions?
If so, there are some key buttons to press in the SAFE import screen.

Let me know if this is the case and I may be able to help.