Steel beam - wood equivalent

[RedNeckRacin]

I believe the 2009 irc is available online and it has girder spans in The flooring section. It will give you available spans lengths for different combinations. I think we need some more information though before even being able to be helpful.

 

[BHD]

you said you have a 4.5 space take the wood and put a 1/2" thick x 4" wide, steel plate on or in the middle of the wood, bolt ii together, and put in the header, the header will be 3.5" wide

if you want steel only used a 4" deep by 3" wide, steel tube, 3/16 wall, and go for it, If still concerned go with 1/4 wall, I do not have any chart but I know it would more than hold the load, the construction and load proprieties of the floor and other are normal.

you do not say the floor load, and width of the floor that is to be bearing on this header, or if there is a wall above it or how it is constructed, (even the floor joists depth), as been stated, one could put the header use the space the joists take up and put some joist hangers on the header to hold the floor joist in the header area, (even if the floor joist were 2x6, and you say you have 4.5" that is 10" of space for a header, and If my recall is correct a 2x10 is only 9.25" wide, add a one by on top of the header to match the top of the joists and put down ply wood sub flooring

 

[Rock knocker]

You can also put the header at the higher floor joist elevation and hanger the floor joists off the beam/header.

 

[LD1]

First question is what load? gotta know the loading. What leads you to the double 2x10 conclusion?

And are the double 2x10's #1, #2, #3, are they SYP, SPF???

A double 2x10 spanning 6' made with #1 SYP (according to my tables) is good for 792 pounds per foot evenly distributed
Same thing made with #2 lumber drop the max loading down to 608# per foot.

4-ply 2x6's are stronger across the board than the double 2x10.

Why do you only have 4.5" of space to work with. Thats not much depth for a header.

But picking 792# per foot that the SYP #1 2x10's can hold, we can now solve for a beam of equal strength.

L/360 deflection would me at max load, deflection not to exceed 0.2"

A simple w4x13 beam can handle that load with ~7800psi max stress (generous safety margin with either 36ksi or 50ksi steel), and a deflection of 0.06" (or about 1/16")

Even lighter weight S-shape 4" beams will handle the load.

So in summary......pick a 4" i-beam and it WILL be stronger than a pair of 2x10's by a significant margin.

But as someone already noted, you gotta have it properly tied to the supports.

 

[radioman]

i am not sure why you are not using a online calculator. I searched for one and this is what i got. Wood Beam Calculator | What size do I need? you can put in the values you need according to your setup .

 

[radioman]

i am not sure why you are not using a online calculator. I searched for one and this is what i got. Wood Beam Calculator | What size do I need? you can put in the values you need according to your setup .