Autodesk Robot Structural Analysis

[#1]

Dear All,

I would like to make the following question regarding lateral buckling length for steel beams  with steel bracket to column faces.

It is considered that the part of the beam which is supported with a bracket is considered not to laterally buckle. When asked to define the lateral buckling length of the beam for the lower flange (negative moments at connection ) i consider the point where the bracket "ends" as a lateral constraint. Is it possible for RSA to consider the full length of the bracket as not susceptible to lateral buckling?

Thanks in advance,

Manos Drakopoulos 

[#2]

You can manually define the restraint at x metres from the ends of the beam.

Or, divide the beam into 3 segments, with the 2 end segments the same length as the bracket.  Then just use the centre portion to do the checking. 

[#3 · Accepted solution]

The picture that illustrates what Tony suggested (thank you Tony for your help) for brackets located at 0.1L from the bar ends. In addition for standard support conditions and load you may assume that the restrains are at the locations where the lower flange is no longer under compression (bending moment changes sign /equals to 0/).

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[#4]

Artur,

Any idea if what you show in picture above is implemented through Api?

[#5]

You can use the following methods in the member type label definition

IntPsClear ( IRDimMembDefIntPsDataType type )

IntPsCoordNum ( IRDimMembDefIntPsDataType type,long* ret )

SetIntPsCoordValueType ( IRDimMembDefIntPsDataType type,long IsRelValue )

IntPsCoordValueType ( IRDimMembDefIntPsDataType type,long* IsRelValue )

SetIntPtValues ( IRDimMembDefIntPsDataType type,long no,double coord,double coeff )

IntPtValues ( IRDimMembDefIntPsDataType type,long no,double* coord,double* coeff )

SetIntPtAddOption ( IRDimMembDefIntPsDataType type, IRDimMembDefIntPsOptionType option, long IsSet )

IntPtAddOption ( IRDimMembDefIntPsDataType type, IRDimMembDefIntPsOptionType option, long *IsSet )

E.g. the parameter option of SetIntPtAddOption can be set as:

   I_DMDIPOT_MANUAL_COORDS

   I_DMDIPOT_IN_ADJ_MEMBER

   I_DMDIPOT_IN_NODES

   I_DMDIPOT_IN_ZERO_MOMENT

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[#6]

Thanks for the replies.

The way i dealt with that specific LTB check is exactly the way you describe it, i just wanted to make sure that there was no other way to specidy that the whole beam's length supported by the bracket is constrained.

It is really nice to talk to you Arthur after about 5 years since i was working for Robot's support here in Greece. I have become a little rusty with the programme but i am now getting back to it.

Regards,

Manos