Instabilities type 1, 2 and 3

[Anonymous]

I made a column as a truss and got lot of errors. No idea what else can I change. I added only self-weight and even though there are 10000m displacements.

[1234eddie]

@Anonymous 

Can you show the Bar End releases?

Gr edward

[Simau]

Hi @Anonymous 

Try to set the 4 column as "simple bar", not truss

[Anonymous]

Sorry for german menu. Gelenke = releases. I tried also to make all the bars pinned-pinned

[Anonymous]

@Simaudidn't work

[Simau]

Can you attach your model?

[Anonymous]

Sorry, that .zip but .rtd somehow doesn't want to be attached

[napooil · Accepted solution]

Set structure type to 3D Frame.As picture

[Simau]

@Anonymous 

You have some weird excenticities, i deleted them

I added  horizontal bars to close the truss

Model attached

[Anonymous]

@napooil   Ok, it works, however I'm not sure if I attached windload properly.

Nevertheless what is the point of designing 3D truss when at the end you need to change it into a 3D frame?

Do I have to set all the bars as pinned-pinned or pinned-fixed or can I leave it as a fixed-fixed?

@Simau  I can't see them. How can I delete them?

[Simau]

Select all the structure then

[Anonymous]

@Simau  vertical displacements are gone (UZ). UX still there.

Can someone explain why after converting into frame my construction works?  Do I have to change then all the bars as pinned-pinned?

[Rafacascudo]

Your original model cannot be qualified as a 3d truss . In this "geometry type" all bars are automatically treated as truss bars. So , all nodes/joints are pinned which makes some of your nodes unstable.

So , that´s why it will only work only if it is treated as 3d frame .On Those unstable nodes above , Shear on the vertical chords would make the structure stable.