equivalent load diagram in etabs 2

[auatipu]

hi,
I'm analysing a multistory concrete building in etabs. I use auto mesh option and auto line constrain. When i investigate force diagram for vertical load of a beam i found one of the equivalent load is upward (marked portion in attached file).But when i remove auto line constrain all equivalent load is downward. What is the logic behind this?

 

[BAretired]

I have no idea what "auto line constrain" in etabs is supposed to do and it sounds as if you don't know either. This brings up the question of using software which you do not understand for the analysis of a highrise building. How can you justify such a practice?

BA

 

[auatipu]

CSIberkley in their website define auto line constraint - Also known as ‘Edge’ constraint in SAP2000, the auto line constraint automatically connects adjacent elements that do not share common joints, such as a coarsely meshed shear wall intersecting with a finely meshed floor slab. Instead of having to manually re-mesh areas/shells or frame elements to create shared mesh points on the adjacent elements, the auto line constraint ‘zips’ them together using displacement constraints. By default, the auto line constraint is turned on in ETABS, but off in SAP2000 (user can modify these defaults).

As my understanding auto line constraint is nothing but a tool that reduce hassle of fine meshing.

@BAretired i m not practicing what i do not understand. I m just want to use auto line constrain without fine meshing manually and want to verify this command that's why i raise this question in this forum.

 

[paddingtongreen]

What does "auto line constrain" connect together in your structure? clearly something is connected and then disconnected. A guess is that one element lifts another when connected causing upward forces to show.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

 

[cooperDBM]

Since your question is software related you should try their technical support.