Extracte link forces

[newman]

Hi seismosoft group
I am trying to extract shear force in x direction for your RC-joint example file which is also define in chapter 4, verification report.
In all of your example, the incremental load is in x-direction, but, when I try to extract the force in x direction (F1) the program show a very small value. The But when I change the considered force to F3, the program give me the shear forces.
Why this happend? I am sure that the shear in the center link should be in F1 direction not F3.

[newman]

I have another question. In these models there is also an axial force. I think that the axial force also should be extracted in the joint by center link. But, similar to the previous problem, the reported force for F1 is very small. Could you please guide me to extraxt the true axial and shear forces from this center link? Not these small value.

[huffte]

Hi newman. If you look at the element connectivity details along with the nodal coordinates, you will see that the Z-coordinate for the initially coincident nodes (13_1 and 13_2) and orientation node 1 (10) are equal for the center link. This tells me that the axial force in the link is indeed F1, while the shear force in the link is F3. You will notice that, for the column links, the initially coincident nodes have the same X-coordinate as the orientation node 1, with differing Z-coordinate. This tells me that F1 is shear and F3 is axial for the columns, as expected. These are true since the model has been set up to make local 1-2-3 for the members align with global X-Y-Z for the model. So, I am certainly no expert in joint modeling. But it seems to me that the shear in the center link is indeed F3, not F1. Perhaps I am missing something though. Best of luck newman.

[newman]

Thanks a lot for your answer. I think that because of the time history loading is in x direction at the top of the column, it needs to a x reaction in joint link. So, the joint should be have two liads: one for time history loads in x direction (F1), and one for vertical loads on the connected beams (F3).
But, the only force which can be extract from the results of these RC joint examples is F3. I don't know why there is no force for F1 in the joint link.

[seismosoft]

Hello Newman,
Note that in the pre-processor you can view the elements local axes, and understand better the members' orientation.

Seismosoft Support

[newman]

Dear Seismosoft,
I don't have any problem with underestanding oriantation. I only want to know that why there is no any force in F1 derection for the joint link while the structure is under horizontal force.

[seismosoft]

Which example are you referring to?

[newman]

Your verification report examples, Chapter 4, RC joints

[seismosoft]

There are six examples. Which one?

[newman]

RC joint 02.