Autodesk Robot Structural Analysis

[#1]

Hi,
Recently I have done a steel frame analysis in Robot 2011 and Can you please answer the following questions:
1. what is the default connections in Robot among the beams or beams and columns in a 3D frame?
2. Is it a rigid or pinned connection?
3. If I apply a pinned-pinned release among the bars structure becomes unstable during the calculation, how can I solve this issue?
4. Do we need to apply pinned-pinned releases among the bars when we do a frame analysis?

Many thanks

Regards,
James

[#2]

Hi

As a default all connections between bars are fixed.

In case of instabilities please upload model or contact me by Private Message

[#3]

Hi Rafal,

Thanks for your reply and I have attached the model with this message.

Regards,

James

[#4 · Accepted solution]

Hi,

Generally - too many releases (wrongly applied, giving instabilities - in this case errors in model).

You can not release bars on pinned supports (-> the same dofs released twice).

My vision of this model attached: fixed supports with released columns, bracings ( 101to108 128to137) as  truss bars, Fixed-Pinned1 releases applied on structure, some relases changed to get rid of instabilities.