Autodesk Robot Structural Analysis

[#1]

Hello,

i need to create a lattice beam between two UPN 300 profiles as shown in the attached picture.

I created first a model with 4 supports that would simulate the connection between the lattice ( upper and lower chords) and the UPN sections.

I did the calculation and the steel deign for this model, and everything is ok so far.

The problem is that now i need to integrate this lattice into the bigger model, where I am unable to put the 4 supports.

In the bigger model I must connect the lattice to beams with UPN300 section.

How would you do this?

I tried to use the Complex Section property and define a Lattice in XZ plane with the post and the diagonal made of TCAR40x4 sections.

The result was not the same.

I'm not shure how the lattice chords (upper and lower) would be defined in this case.

[#2 · Accepted solution]

Try to create the dummy bars from the nodes of UPN 300 up and down to the nodes of the top and bottom chords of the lattice. This is similar to the solution I proposed for http://forums.autodesk.com/t5/Autodesk-Robot-Structural/Rafter-on-wall-problem/td-p/3363029

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.

[#3]

I agree and I will use the short dummy bar solution.

But I would still like to know how to corectly use the Complex Section - Lattice option. Maybe it will come in handy some day and I'm not shure how it works.

[#4]

This option is primarily intended for verification of complex columns under the compression force. I'm attaching some verification examples in Polish done for Polish steel code but looking at the pictures you should be able to find out what is the range of application for this option.

[#5]

Nice!

I got it now, thanks! Tried modeling and it worked. Further, I have to test it sometime.

Case closed

P.S.

It's such a nice feeling when you learn something new... Even if it's a minor thing, it usualy is a starting point for further reaserch.