Direct analysis method

[HoshangMustafa]

Hi all

Please find the attached file.

This is to model Example 3.1 of AISC design guide 28. I modeled bracing as tension member as suggested in post 4 in this thread:

https://forums.autodesk.com/t5/robot-structural-analysis-forum/steel-bracing-advanced-bar-properties...

So, how to manage Direct analysis method with this model?

Description of Framing
All lateral load resistance is provided by the tension only rod bracing. The tension rods are assumed to be pin connected using a standard clevis and pin (see AISC Manual Tables 15-3 and 15-7). Beams within the braced frame are bolted into the column flanges using double angles (see AISC Manual Figure 13-2(a)). A single gusset plate connecting the tension rod is shop welded to the beam flange and field bolted to the column flange (see AISC Manual Figure 13-2(a)). All other columns outside the braced frames are leaning columns with simple beam-to-column connections.

[Krzysztof_Wasik]

Hi @HoshangMustafa 

Description in help regards bar members subjected to  tension, compression, shear and bending.

[Krzysztof_Wasik]

Hi @HoshangMustafa 

I think that description in help regards bar members subjected to tension/compression, shear and bending.

[HoshangMustafa]

Thanks, @Krzysztof_Wasik 

In my correct model in post 31, I tried using compatible node with rotation about Y axis by 26.6 degree for the members 14&15 after removing the tension only property from the members 14to17. But I couldn't manage the compatible node for them.

[Krzysztof_Wasik]

Hi @HoshangMustafa 

Share your file

[HoshangMustafa]

Hi @Krzysztof_Wasik 

I'm sorry I didn't refer to the exact model in my last post.

Here is the model.

[Krzysztof_Wasik]

Hi @HoshangMustafa 

I do not see any compatibility defined in your model I could help with.

I do not know what kind of compatibility you would like to have.

Describe what kind of effect, regarding force transfer between bracings you would like to simulate.

[HoshangMustafa]

Hi @Krzysztof_Wasik 

I do not see any compatibility defined in your model I could help with.

I do not know what kind of compatibility you would like to have.

Describe what kind of effect, regarding force transfer between bracings you would like to simulate.

It's just for learning. Do whatever rotated compatible node in bars 14&15.

[Krzysztof_Wasik · Accepted solution]

Hi @HoshangMustafa 

Attached you will find modified f ile

[HoshangMustafa]

Thanks, @Krzysztof_Wasik 

Very appreciated.

[HoshangMustafa]

Hi @Krzysztof_Wasik 

May I describe compatibility node in words?

Say you have two intersecting bars and each bar is divided into two parts. Using compatible node at the intersection point for two parts of one bar and blocking any d.o.f will make the force diagram corresponding to this d.o.f continuous over these two parts of the said bar, regardless of the fact of its intersection with the other bar.

[HoshangMustafa]

Hi @Krzysztof_Wasik 

Sorry for spelling uncorrectly.

May I describe compatibility node in words?

Say you have two intersecting bars and each bar is divided into two parts. Using compatible node at the intersection point for two parts of one bar and blocking any d.o.f will make the force diagram corresponding to this d.o.f continuous over these two parts of the said bar, regardless of the fact of its intersection with the other bar.

blocking should be read as unblocking.

force means (force or moment)

regardless of the fact of its intersection with the other bar

This means that this force or moment will not be distributed (transferred) to the other bar.

[HoshangMustafa]

Hi @Krzysztof_Wasik 

Is my interpretation correct?

Another thought.

We entered an angle for the rotated compatible node. Could it be entered as aligned with a member instead of inputting values? I think if the loads are large, inputting angles for the rotated compatible node maybe incorrect.

[Krzysztof_Wasik · Accepted solution]

Hi @HoshangMustafa 

Your  interpretation is OK.

Angle while compatible nodes definition should be defined manually.

[HoshangMustafa]

Thanks, @Krzysztof_Wasik 

Your response is highly appreciated and made better understanding of compatible node.

[abdirahmanabdulllahia]

i have question related to leaning column when i wanna to make leaning column i should release my beams do release my beams rotation in direction Rz only or i should release all direction i wanna to use simple shear connection like shear tab