Etabs and Safe Reaction Loads Differ

[Chris-Eng]

Good day,

I have a 4 story concrete building, shear walls, flat slab floors and roof with concrete beams and column. The model was completed in etabs, (no errors)and pier labels were added to the walls. An Axial Force Diagram was done in Etabs to show the loads acting at the reactions and wall loads. The floors were then exported to safe (Floor loads & loads from above) and Load reactions checked (both point reactions & Integrated wall Reactions). When comparing both load diagrams the point loads as well as the wall loads differed.
The differences were large. What could be the reason for this?

Wall Modifiers - m11 = m12 = m22 = 0.1, f11 =f12 =f22=0.35
Beam Modifiers - I22 =I33=0.35
Column Modifiers - I22 =I33=0.70
Slab - m11 = m12 = m22 = f11 =f12 =f22=0.25

Etabs model is below along with screenshots of the force reactions

https://files.engineering.com/getfi...6f-454e-ba56-20edad69423a&file=Etabs_test.EDB

https://files.engineering.com/getfi...56-48be-8392-09b610042bfb&file=Safe_Loads.png

https://files.engineering.com/getfi...4-4df6-a1e5-c5dd7dbb995a&file=Etabs_Loads.png

 

[sticksandtriangles]

Interesting screen shots, and not directly related to your question, but are your walls meshed in etabs or are they one solid wall element?
Etabs understands what a "pier" label is, but safe does not understand what this label means. Safe will only understand where the wall is meshed and will place nodal reactions at the meshed wall locations.

I would not expect the SAFE screen shot to have a singular load applied for each of the "perimeter" walls, but rather a continuous line of point reactions where Etabs has internally meshed the walls.

Also see this thread:

https://www.eng-tips.com/viewthread.cfm?qid=444536

see my response there and let me know if this is your case as well.

S&T

 

[Chris-Eng]

Thanks S&T

To answer your first question Yes, the walls were meshed in Etabs.

From your previous thread the question "Is this a model where you are replacing existing reactions with new reactions?"
No i am not replacing the loads... I am comparing/questioning the loads shown in etabs vs that shown in safe and the major difference.
Also Safe can give a single load reaction for a wall if the "integrated wall reaction" is checked instead of the "point loads" option.