Joists as lateral bracing for steel beams 2

[irizarry]

Can regular steel joist sections act as lateral bracing for beams top flanges in SMF?

 

[irizarry]

I forgot to ask, is it necessary to brace both sides of the beams to consider it laterally braced?

 

[msquared48]

Are you talking about light gage steel joists, or open web steel joists?

Open web, definitely.

Light gage steel... I would say it depends as to how "light" the gage of the member and the depth.

As for both sides, no. If connected properly, one side should be sufficient. We have perimeter beams all the time that are braced this way.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[asixth]

What are the joists, what are they fabricated from and what section do you want to restrain?

If the joists are cold-formed sections (say 150mm deep with a base metal thickness of 1.2mm spanning 3000mm) and the cleat (8mm plate say) is either welded to the top flange (so the joists past over the beams) or below the top flange (so the joists are in-plane with the beam) of a hot rolled section (say W14 beam), then I would think it is acceptable to say that the joists restrain the top flange for lateral-torsional buckling.

Remember you have to prove that the joists can restrain the compression flange with a minimum of 2.5% of the flange force.

 

[paddingtongreen]

I would say the joists do provide lateral restraint if they are properly connected, and, if they themselves are laterally restrained or strong enough to function as struts.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[irizarry]

Sorry it took so long, I was away for a couple of days.
The frame is made up by W14 X 109 columns, same section for girders supporting the joists, and 22K7 steel joists. The beams connecting the frame in the direction of the joists are W12 X 65. I uploaded a small drawing showing one bay.
The roof is a steel deck with 3 inches of lightweight concrete.

So could I use the joists as lateral bracing (top and bottom flanges) for W14X109 beams? If yes, is there typical connection for the bottom bracing (like some angle connecting from the joist to the bottom flange of the beam)?
Also, for the W12X65 beam I'm going to connect it to the roof using shear collectors, which I think could give lateral bracing as well. Is there a connection for bottom bracing from shear collectors?

I know it's alot of questions, but anything you guys can advice will be greatly appreciated.

 

[slickdeals]

I recommend the following publication.
Designing with Vulcraft Steel Joists

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[irizarry]

Thank you Slickdeals, I already have that guide.

 

[slickdeals]

You may also want to see

http://steeljoist.org/LiteratureRetrieve.aspx?ID=37373

We are Virginia Tech
Go HOKIES