Structural steel connection top of column 1

[rookie96]

Hello,

I am currently designing a 19m x 6m x 3.7m(height) structural steel shed to cover outdoor chiller water pumps. I tried searching online for roof beams connection (for perpendicular beams on top of column) but could not find anything similar, my question is which of the two connection methods will be more stable, as in beams connected to the columns (bolted) or beams connected to each other on top of the column, in this simple structural steel frame. (note that there are no loads in the roof other than insulated corrugated sheets)

 

[Enable]

Pretty much any option you can fathom could be made to work and will likely come down to the forces involved and local fabricator preference. But I would first take a step back and really nail down the intended load path. For instance can you explain how you're dealing with lateral loads perpendicular to the longitudinal direction of the building? Are you trying to achieve portal frame action or are we using cantilevered columns or braced frames or something completely different?

 

[dik]

Either work well. Can you make the 4 span continuous, or two two-span continuous... just easier.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[HTURKAK]

I would prefer second option. Moment connection to major axis of column and simple connection to minor axis. The top level of column soffit with beam .
I will suggest you to consider the bracings and fixed column bases.




He is like a man building a house, who dug deep and laid the foundation on the rock. And when the flood arose, the stream beat vehemently against that house, and could not shake it, for it was founded on the rock..

Luke 6:48

 

[milkshakelake]

Others have explained it pretty well. In my experience and my area, it's always the second option. It's how fabricators do things around here. Your mileage may vary.

Getting a cap plate to do a moment connection (i.e. portal frame) is possible, but it's not a simple calculation like what is presented in my local code (AISC Steel Construction Manual).

 

[dik]

rotate your corner columns 90 deg...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[BAretired]

Column webs parallel to the short direction seems right to me.

 

[dik]

by rotating the corner columns, you gain flexural stiffness in the long direction. It makes little difference as far as the connections go. They are all relatively simple.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[sdz]

Are you in Australia? Wind loads might be significant. You will be designing as monoslope free roof, blocked under.
Assuming you have pin based columns then you will need moment connections at the top for stability, hence option 2 is preferred.
Keep the columns oriented as you've drawn them. The wind load at least will be much higher when at right angles to the long edge.
If you can use bracing in the long direction, even if only one bay, it will help a lot. Or knee bracing over multiple bays.
Do you have a senior engineer you can talk to?





Ooo eee ooo ah ah ting tang walla walla bing bang
Ooo eee ooo ah ah ting tang walla walla bing bang

 

[rookie96]

Thank you all for your valuable information. I include in the image below bracing proposal after trial and error with analysis. (Note that this design will be submitted to other engineers and consultants for further review.)

 

[HTURKAK]

@rookie96 (Structural)(OP);

I would try to provide moment frames in both directions. Rotate the 2nd and 3rd columns 90 degrees at both long. axis to get 2 moment frames at long direction and 3 moment frames at short direction.
With this , option you may delete VB's.




He is like a man building a house, who dug deep and laid the foundation on the rock. And when the flood arose, the stream beat vehemently against that house, and could not shake it, for it was founded on the rock..

Luke 6:48

 

[dik]

I'd likely have the roof framing acting as a diaphragm, rather then the cross bracing in the roof.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[SE2607]

Ignoring the need to resist lateral loads, I would suggest something in between 1 and 2 meaning having the top of column flush with the top flange of the beam and use 3 shear clips, 2 at the corners.