IMPORT CROSS SECTION

Hi everybody,

Often in our costruction, like truss, we use 2L profile section.

In Karamba unfortunately there isn't them.

Do you think that it is possible import the file EUR.PRO of sap2000 for generate a complete table of section profile?

I know that in Karamba we can use the function "read cross section table" but I'd like to know if someone had the same problem.

Kind,

Marco

Replies to This Discussion

Permalink Reply by Karamba3D on February 3, 2015 at 12:29pm

Hi Marco,
at the moment Karamba 1.0.5 does not support the display of 2L profile sections. It is however possible in the cross section table to define the displayed geometry of the cross section independently from its mechanical properties (A, Ay, Az, Ixx, Iyy,...). If the SAP-table contains all the necessary information it is thus possible to turn it into a table readable by Karamba.
Problematic would be un-symmetric cross sections like C-profiles where the center of gravity and the center of shear do not coincide. In Karamba it is assumed that external forces act at the center of shear (i.e. produce no torsional moment).
Best,
Clemens

Permalink Reply by Marco Pellegrino on February 3, 2015 at 1:43pm

Hi Clemens,
Thanks for your reply.
In these day, I have defined my cross table and seem thai it works good.
If I use L profile in truss and the load is only at its joint, Iyy Izz Wt ect ect affect my analysis?
I think NO but I'd like to have a response.
At least, I have used your cross section optimization and I have a doubt.
In planar truss, I constrain every joint with "ty" for run analysis without the messale error "singolarity stiffness".
Now, what is the buckling lenght readed by algorithm?
Sorry for my English but I'm learning it.
Best,
Marco

Permalink Reply by Karamba3D on February 4, 2015 at 12:15am

Hi Marco,

when using truss elements Iyy, Izz, Wt, etc. do not affect the structural response.

The cross section optimization algorithm however takes buckling into consideration and therefore the bending properties. In order to avoid this use the 'ModifyBeam'-component and set 'Buckling' to false.

A beam can be turned into a truss via the 'ModifyBeam'-component: Set 'Bending' to false. Then you do not have to define extra hinges at the ends of the truss element.

For details regarding the bending lengths of individual members please see the manual.

Best,

Clemens

Permalink Reply by Marco Pellegrino on May 10, 2015 at 10:56am

Hi Clemens,

I have seen your presentation at UCL last week. Thank you for join with student as me.
I have created my cross section table to import 2L profile into Karamba.
It was easy extract all the stiffness component from SAP2000 but impossible to show properly the cross section image into rhino. And here come out my doubt.

Which rule does the software use to compute the mass structure?
Mass of one element= AREA CROSS SECTION*Lenght*Density? is it right?

Regards,

Marco

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