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Replace a W-Girder with a Joist-Girder
4

Replace a W-Girder with a Joist-Girder

Replace a W-Girder with a Joist-Girder

(OP)
Where can I find an easy way to replace a W-Girder with a Joist-Girder?

RE: Replace a W-Girder with a Joist-Girder

Hire a structural engineer who knows how to do it?

You don't provide enough information here to allow a reasoned answer.

RE: Replace a W-Girder with a Joist-Girder

(OP)
JAE,

Thanks. You are right. I didn't provide enough information. I will give you some details:
What I would like to do is to use Joist Girders instead of W Girders to make the frames I design more economical. I start doing some research and I saw this information about TECHNICAL DIGEST #11 - DESIGN OF JOIST GIRDER FRAMES (July 1999),  "Joist Girders provide an economic structure you may not know of the added economy afforded through the use of the Joist Girder/Rigid Frame concept."
But I have some doubts even before I start using them and the reason is this:
I tried before to use Cellular Beams instead of regular W Beams for the rigid frames the company I work for is designing, but talking to a the Midwest Regional Manager of
CMC Steel Products he discouraged me, saying that his company is not interested in providing small amounts of Cellular Beams. They now have a lot of work for areas like
Las Vegas, to give me an example.
My question is: from your experience what should I do succeed this time in my attempt to replace the heavy W Girders with Joist Girders?

RE: Replace a W-Girder with a Joist-Girder

Joist girders are used much more frequently in your situation than castelated beams.  If you have joists, also specifying joist girders is just adding more product from a supplier you already have on board.

I don't see a problem.

RE: Replace a W-Girder with a Joist-Girder

Most of the Wal-Marts, Lowes, Home-Depot, etc. in my area use joist girders...

As EOR you will need to do your homework on providing the right info to the joist manufacturer and coordinating details.

This Vulcraft catalog might give you some useful information to start with; see p 78:

http://www.vulcraft.com/downlds/catalogs/joistcat.pdf

RE: Replace a W-Girder with a Joist-Girder

Are you looking to include the joist girders in the LFRS or only for gravity?

RE: Replace a W-Girder with a Joist-Girder

(OP)
JAE
&
JKW05,
Thank you for your useful information

UcfSE,
I am sorry, but I am not sure what LFRS stands for

RE: Replace a W-Girder with a Joist-Girder

Lateral force resisting system

RE: Replace a W-Girder with a Joist-Girder

(OP)
dgkhan, thank you.
My answer to UcfSE is YES.

RE: Replace a W-Girder with a Joist-Girder

I looked thru the vulcraft joisy girder manual. They only
show gravity loads. Doesnot meen that joist have no axial capacity. But I will like to see how joist manufacturer being designer too handles this. By the way RICI, economy of joist sometime cause vibration problems.

RE: Replace a W-Girder with a Joist-Girder

Check out this publication:

"Designing with Steel Joists, Joist Girders, and Steel Deck"

Click on the link in that page just above the title of the publication I referenced.  It is not expensive and provides some details and design guidelines for using joists and joist girders in moment-resisting frames.

You may also check out the Steel Joist Institute Catalog for additional information or requirements.

RE: Replace a W-Girder with a Joist-Girder

The economy of joist girders needs to include the components of walls/stairs/columns since the increase in depth over rolled shapes, (which causes the economy in weight), also causes a increase in floor to floor height or floor to roof height.

RE: Replace a W-Girder with a Joist-Girder

(OP)
dgkhan,
If I will use the Steel Joist only as a Roof Girder,
I hope that the vibration is not a problem anymore.

UcfSe,
Thanks. I will check out "Designing with Steel Joists, Joist Girders, and Steel Deck"

Civilperson,
Yes. The increase in depth is an issue. Thanks.

RE: Replace a W-Girder with a Joist-Girder

Agreed, the Vulcraft tables are only for gravity loads.  But starting on page 78 they discuss their process for providing Moment Resistant Frames. As I said before, using joist girders in a moment frame will require some homework to perform a lateral analysis.  If you can, contact a joist manufacturer and they may be able to provide you with some preliminary member properties for use in a frame analysis.

RE: Replace a W-Girder with a Joist-Girder

(OP)
JK05

Thanks. Good point.

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