flexible diaghram

[Anonymous]

i have applied flexible diaghram with no fe to all floor panels instead of Shell  after that i get to many instability type 1 problems and beams and columns take to much moments and axial force, im talking about like 1000000000 knm and so on for a beam when it should take 1200 knm. What could be the problem and how to solve this?

[Artur.Kosakowski]

Lack of bracing  for a model with pinned supports? 

[Anonymous]

i can send you model so you can take a look at it

plenty of errors and to many instability types i dont know what cause this because when i have Shell on slabs the instability type 1 dont appear and i dont get so big diffenrences in moments and axial forces..

[Anonymous]

https://fil.email/1Cacxs

[Artur.Kosakowski · Accepted solution]

When you don't have surface elements and diaphragms are intended for lateral stiffness (UX UY rigid links used) you cannot place a column on a floor as there is nothing to prevent its vertical movement. You have to have either a wall or a column or a beam directly under it. 

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