I Beam for structural support

[crazyal]

Beamboy didnt list a w21x50 beam so I went down one size to a w21x44, and given a 32' span, that beam would hold a distributed load of 1100lbs PER foot safely:thumbsup:

So now if you 1100lbs and divide by take HALF of the length of each floor joists comming into each side, (since the other half is supported by the walls of the building) that would give you a safe psf rating. Take about 10lbs off of that for the dead load.

The steel company I deal with actually has an engineer so I let them figure it out. I probably could have gone with the 44 but their supplier had a 35' w21 50 in stock so they gave me a good price. The footprint is 28'x32' so the floor joists are about 13'6". Neither the front wall or rear walls support any of the floor load so it works out to to about 420 sqf on the i-beam (half of 840). Because it's storage they usually figure higher load ratings than "livable" space since you are more likely to stack boxes and leave less room to walk. I think we went somewhere between 60psf to 80 psf. (70psf x 420sf)/ 30' = 980 lbs per foot. There are no internal walls.

I could have gone smaller and still be fine but it wouldn't have saved much money (since the price is by weight) and since there's a little extra safety factor I can have a bean trolly to move loads (say up to 1/2 ton) around if needed. Around here 80psf for a snow load is not out of the question. Since I have trusses it wasn't an issue but a trip to Lowes and you'll find they have a chart right at the contractors desk for snow loads in your area.

 

[crazyal]

His floor may indeed have more load than your roof. The problem with your situation is that in concentrates the roof load onto only TWO points on the beam instead of being evenly distributed like floor joists. ANd without knowing all the variables for sure, Remember I metioned a 16x40 is what you would need. So yea, the beam he used would work in your case also.

I can add as many vertical supports as necessary to evenly distribute the roof load couldn't I? Wouldnt that accomplish a similar effect of the floor joists against the beam? As far as the beam supports I planned on doing something comparable to crazyal's set up. Would it help if I upload a pic of my current set up with a drawing of what I plan to do? Its going to be a really rough drawing... but it will depict the basic idea of my approach.[/QUOTE]

Since you don't have trusses I would find out what to use for a snow load so you'll know what to expect on the i-beam. It'll be a little complicated because the side walls will support part of the weight as well as the end walls. Then if your going to have any sort of floor or storage you'll have to add that in. Then I would call around to get prices. I found that the steel companies like to deal in 5' increments (25', 30', 35') so if you need 31' you'll be buying a 35' i-beam. Check to see what they have in stock, that could also mean a savings. Finally you can pour pads for the posts and set the vertical posts and i-beam and then pour your floor for a smoother finish.

 

[shibaura_4043]

here's a couple of rough drawings of my plan.... any suggestions how to improve? As far as snow load goes...I live in North Texas not sure thats a huge concern.... but then again the old saying wait five minutes and the weather will change here in texas comes to mind!

 

[crazyal]

I've seen people use wood to make a beam like your talking about. I've even seen one that used tension rods as well. You have a lot of room to work with.

 

[shibaura_4043]

I've seen people use wood to make a beam like your talking about. I've even seen one that used tension rods as well. You have a lot of room to work with.

the I beam I need will be around 600.00...unless the wood beam is extremely cheap I think the steel I beam would be worth the cost for the additional functionality it offers(trolley w/hoist)

 

[gumshu]

Hello, Iam looking for a couple opinions... I am planning to upgrade my exsisting pole barn to a shop/workspace, I plan on pouring a slab in the barn (30X30) and I would like to replace the two middle poles that support the ridge with an I beam acoss the barn at 12' high with supports from the I beam to support the ridge. What size I beam would you guys recommend? Is this doable? whats the best way to brace the beam and tie into the building. I would also like to use this beam for an electric hoist that travels the length of the beam. The local steel shop recommended I use 10" 12lb I beam for the 30' free span. Anyone have a clue how much this beam will weigh? Lastly anyone have any suggestions on what to add to the pole barn before I have the slab poured.... Im considering a full bath... is it worth the extra effort and $$? Thanks

In order to do something similar in my barn, I had to use a scissor truss for that length which spanned.... 24 feet or so. You may just want to speak with an engineer about that span and weight bearing.

 

[shibaura_4043]

thanks for the advice gumshu... the local steel shop has a staffed engineer, tomorrow I may see what it would cost to have him come out and make a recommentdation on the best approach.

 

[mjncad]

After looking at your pictures, you'll definitely have to convert those rafters to a truss system, and need a stout beam to bridge that span. If you do it right the trusses can be separate from the beam, leaving the beam to be nothing more than a trolley track.

 

[shibaura_4043]

After looking at your pictures, you'll definitely have to convert those rafters to a truss system, and need a stout beam to bridge that span. If you do it right the trusses can be separate from the beam, leaving the beam to be nothing more than a trolley track.

so you dont think my drawing on the picture will be sufficient? (assuming the beam is the correct size), starting to sound like this may be more trouble than its worth. Maybe I should just live with two poles as the support.

 

[LD1]

The steel company I deal with actually has an engineer so I let them figure it out. I probably could have gone with the 44 but their supplier had a 35' w21 50 in stock so they gave me a good price. The footprint is 28'x32' so the floor joists are about 13'6". Neither the front wall or rear walls support any of the floor load so it works out to to about 420 sqf on the i-beam (half of 840). Because it's storage they usually figure higher load ratings than "livable" space since you are more likely to stack boxes and leave less room to walk. I think we went somewhere between 60psf to 80 psf. (70psf x 420sf)/ 30' = 980 lbs per foot. There are no internal walls.

I could have gone smaller and still be fine but it wouldn't have saved much money (since the price is by weight) and since there's a little extra safety factor I can have a bean trolly to move loads (say up to 1/2 ton) around if needed. Around here 80psf for a snow load is not out of the question. Since I have trusses it wasn't an issue but a trip to Lowes and you'll find they have a chart right at the contractors desk for snow loads in your area.

Seems I wasnt too far off in my estimation:thumbsup:

shibaura_4043:

The pics definatally help. And adding more vertical posts will certainly help distrubute the roof load. BUT the roof load is still a big unknown. We need to knwo what it was designed for. Until then, we are just speculating. But we can get close but need a little more information.

For starters, I dont remember if you mentioned, but how wide is the building in the direction the rafters are running, what size are the rafters (they look like 2x6??) and how far appart are they spaced.

If we knwo this, we can do a little reverse engineering to see how much load the rafters can handle. Knowing that we can better get an Idea of how much load the roof was designed to handle.