Cold formed flitch beam

[jplay2519]

What are your thoughts on using cold formed steel back to back between lvls to make a flitch beam where a certain A36 steel thickness isn't available in a reasonable time limit. Design the steel to work and bolt through.

 

[KootK]

So plate stock cold form, right? Not cee's? Sounds alright to me.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[jplay2519]

I was actually thinking cees

 

[KootK]

So the LVLs will be fit between the cee flanges? How is the load applied? To the top of the cees or the side of the LVLs? What is the beam bracing situation?

With your plate elenent now flanged, will the LVL still add anything meaningful to the strength of the beam?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[dhengr]

Jplay2519:
With lt. ga. stl. sections, how do you achieve bearing and load transfer under loads and at the end reactions, and btwn. the two different matr’ls? With that thin stl. matr’l. can you get good bearing/shear/load transfer with through bolts or other fasteners to really make the beam act as a composite member? If you can’t get a 1/4" stl. pl. the right length and width, why not use a 3/8" pl., or whatever, which is available. You might be better off putting the cold formed cee’s on the outside. That way you can fill the web holes with fasteners, with some better degree of certainty, for load transfer. Then provide bearing blocking at reactions, to make both matr’ls. bear.

 

[XR250]

I don't see this as being a problem. Do you actually need LVL's or are they just transferring the load into the CEE's?

 

[jplay2519]

I appreciate the responses. I was putting the LVL's up so that you can attach the joists wood to wood with joist hangers. The joists will frame into the side of the LVL'S. I would think that through bolting would get the loads transmitted through both materials but maybe not?

 

[KootK]

I would think that through bolting would get the loads transmitted through both materials but maybe not?

Sure, if the numbers work. Is this really back to back CEE's and not a box section?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[XR250]

I was putting the LVL's up so that you can attach the joists wood to wood with joist hangers.

I guess I was asking if you could use dimensional lumber instead of LVL's. Why use 'em if the loads do not require them? They cost more.

 

[jplay2519]

Didn't even think about that. Design the cees to take the load and just use dimensional lumber for attachment.

 

[BUGGAR]

You have to match their deflection in design. Can you easily calculate the deflection of your cold formed shape? The AISI equations look complex. Can you get an equivalent EI for your shape?

 

[XR250]

Not is they are just being used as a nailer. The section properties for the CEE's are tabulated in most manufacturer's catalogs or SSMA.