I Beam for structural support

[shibaura_4043]

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

 

[E/S]

Can't help with the beam.
But for me the full bath would be a marriage saver, I work in sewer maintenance.

E/S

 

[CDN Farm Boy]

The 12lb would usually refer to it's weight by foot so 360 lbs but that doesn't sound near heavy enough for that span to me. Perhaps they/you missed a number? For 10" wide flange, my supplier offers 22, 26 or 33 lbs/ft. If it weren't for the hoist, I'd convert the existing rafters to trusses by adding webbing and you wouldn't need the beam at all.

 

[MotorSeven]

I did a 32' x 12" I beam to support a deck(supported at each end only). I don't think I would go a 10" since the 12" still has some bounce to it when walking on it. My DK40SE lifted it 11' to set it with no problem so I am guessing around 1800-2000 lbs.

 

[Raspy]

I believe I beam is rated by how much it weighs per foot. So, if yours is called 12lb, and it's 30 feet long, it would weigh 360 lbs.

However, that seems very light for an I beam that would be used for a traveling lift. I have some 12" H beam that is called 65 lb. That's more like it. But you didn't say what you want to lift. I'm sure there are tables you could use to match your proposed load to a 30' span.

Much more info needed to know the load from the roof and the load from the lift, combined. You might also consider posts that are only 10' apart to significantly increase the strength by reducing the span.

For a full span, holding the roof up and some engine lifting, you might want some 24" I beam with a 3/8 wall. Just guessing. Look it up after making a couple of calcs. There's a lot more to it than simple guessing, and I'm not qualified to do that for you.

 

[shibaura_4043]

I hear ya... I drove a jet truck for a municipality for 4 years or so...dont miss the smell of a stopped up main one bit!!!

 

[shibaura_4043]

I believe I beam is rated by how much it weighs per foot. So, if yours is called 12lb, and it's 30 feet long, it would weigh 360 lbs.

Thats what I thought too... but a 10" beam 30' long has to weigh more than 360lbs. Plus the steel yard said it could handle the 30' free span and the electric hoist load.... the hoist will mainly be for engine pulling but Im sure I'll come up with other useful ideas.

 

[shibaura_4043]

Maybe I misunderstood him... I was on my cell phone... I call tm to verify the lbs.

 

[KennyG]

Apparently they quoted you a M12x11.8 beam. This is kind of special lightweight beam. It is only 11.8 lbs/ft because the web material is only 3/16" thick and the flanges are only 3 inches wide. I don't have my beam tables with me and don't feel like doing the calcs, but I would hesitate to use a 30 foot long beam with this light of webs without some kind of lateral bracing to limit buckling and deflection. My off hand guess is that you should look at a W12 beam with about twice that weight, say a 19 or 22. This would have a wider and thicker flange. Of course, the 3 inch flange might be best for the trolley, but using a beam as a structural member should require a wider flange.

 

[KennyG]

Just re-read and realized you said a 10" beam. That would be a M10x12 and the flange would be close to 4 inches. Still pretty thin web.

 

[Rock knocker]

Plus the steel yard said it could

How would they know, unless they sent an engineer over, or you gave them a pdf of your structurals? At which point, who are we to second guess a PE

From a wise man on ContractorTalk
Structural Advice - Framing - Contractor Talk

I have been a framing contractor for 25 years and I have not yet seen it all. When I think I do, I drive by a jobsite where the framing contractor has neglected to read the truss specs carefully for piggy back trusses and are lacking proper bracing. It is my duty as someone who knows better to stop in and remind them to carefully read the truss specs on bracing and how their ignorance at erecting the system will fail and possibly kill someone.

I've seen many threads here asking for structural advice and personally, it's not any of my business to give out structural advice. We owe it to the people who request this here to steer them in the right direction and that direction is straight to an engineer, architect, or lumber yard who has a qualified, in-house engineer who will have a stamp that can and will stamp a set of plans for you.

I am a framer, not a structural engineer. I don't design structures. If you are a responsible structural engineer, you already realize that unless you are personally standing right there looking at the particular situation, you would know better than to respond with "you need this size" because YOU DON'T KNOW THE WHOLE SITUATION and will be liable for structural advice!

When it comes to framing, I am responsible for putting the structural members in the place where the architect, engineer, or designer tells me to put them. Period. That is my liability. It is also my responsibility if I put something in that is sadly undersized. As a framing contractor, I must possess general knowledge of what is needed structurally for the building. This is not a business trade that you just pick up a hammer and say "I'm now going to frame homes for a living" If something is undersized, a call to the structural designer is needed.

Floor joists? That is a gray area. You can easily find span charts in the code book and online. However, youstill need to know what your local codes are for your situation. Same with your wood species. Same with the modulus of elasticity. Same with the deflection.

To someone who responds to a question, are you going to take full responsibility for someone's floor being bouncy? Are you going to place your signature on a piece of paper saying that it is right for the situation and if something fails or isn't satisfactory, then you will bear full responsibility?

Rafters? No. Because you will have no idea what the snow loads are, or what the roof is really carrying, or what the local code says you need for live and dead loads or what is REALLY going on at the specific site and situation. These loads differ from community to community. Where I live, oceanside is lower than inland. Mountains, different even still. Ours is 40#, the next town over is 60#

Beams? Not a chance. There is no possible way for anyone to be able to tell someone else online what their exact conditions are.

Please stop giving advice on what you think "should be good enough". If you are not doing the calcs for the OP and giving them your state issued stamp of approval on a set of plans, stop giving this advice before you kill someone. This is not a game. This is structural design.

 

[Raspy]

How would they know, unless they sent an engineer over, or you gave them a pdf of your structurals? At which point, who are we to second guess a PE

That sums it up very well. If you don't know the load, you don't know the material. And a parts guy behind the counter is not a structural engineer.

This is not rocket science, so look it up and adjust your spans, if necessary, to make it practical for you. Never build your building, and risk your life with hoists, based on online speculation from others who don't know either, and don't know your conditions.

 

[shibaura_4043]

How would they know, unless they sent an engineer over, or you gave them a pdf of your structurals? At which point, who are we to second guess a PE

That sums it up very well. If you don't know the load, you don't know the material. And a parts guy behind the counter is not a structural engineer.

This is not rocket science, so look it up and adjust your spans, if necessary, to make it practical for you. Never build your building, and risk your life with hoists, based on online speculation from others who don't know either, and don't know your conditions.

I understand he isnt a structural engineer, he made a minimum recommendation based off what I told him... the purpose of the beam is to open the barn up to move equiptment around easier without poles to get in the way.... so the span has to be 30' long. I posted this question because I thought someone might have already experienced a similar situation. I am merely looking for suggestions.... personally if you dont seek input from others you may overlook something very important... while I dont plan on installing the beam based solely off other peoples suggestions.. it does help you form a consensus of the "norm". Thanks for your input.

 

[mjncad]

Shibaura:

To be safe, I suggest you consult a structural engineer. I'm no structural engineer; but that beam the steel yard suggested is way too light for the double duty you want it to do.

 

[bcp]

Two thoughts come to mind, but you may have already thought of them.

Separate the functions-use a truss for the roof and a beam or a wheeled gantry crane for the hoist.

Don't put lots of "engineering" work into the beam and neglect the posts or support system for the beam.

 

[shibaura_4043]

mjncad: thanks for the advice, I tend to agree..... bcp: your thoughts have crossed my mind but would like to kill two birds with one stone if its practical enough... the hoist was an after thought to installing a beam its not a necessity... to me the beam seems like a simpler solution than adding truss but I could be wrong... Is it safe to assume a truss system would be bit more cost effective than an Ibeam?

 

[bcp]

Just for the roof support, I would expect the truss to be less expensive than the beam. For a combined function, I don't know.

Bruce

 

[shibaura_4043]

bcp... I think so too...I 'll get a couple professional opinions on what size beam I will need and then decide on which support system to go with. Most likely cost will be the deciding factor.

 

[Shield Arc]

If you knew your loads you'd have a fighting chance to pick out a beam. There are books with charts, and charts all over the Internet. But you need an engineer in the worst way.
Here is a wide flange chart I scanned, for point loads divide the capacities in half. I'm only giving this to you so you can see there are charts everywhere, but you need an engineer!

 

[LD1]

If you are handy with math, and do your homework, beamboy is a great tool for beam sizing.

As others have said, dont take the sales-guys advise. He dont knwo your loads. And I nor anyone else here does either. All we can do is guess and speculate, so I will give my best guess.

For starters, we dont know the roof load. But since it is a rafter and ridge beam, and you mention two vertical posts supporting the ridge beam, I will make an educated guess here....

Since the end and side walls also share the load of the room, and I will assume the vertical members are evenly spaced @ 10', and the building being 30' wide, Each post is supporting a roof area of roughly 10' x 15'...or 150 sq ft. Now I dont know what your roof is designed for so just guessing that live and dead loads will add up to ~50psf. So each vertical member should be capable of holding 7500lbs.

So now we need to size a beam, 30' clear span, able to hold two 7500lb loads @ 10' and 20', AND for a trolley/hoist. Lets just size that for 1-ton. Loading will look something like this

And based on THAT, you would need a w16x40 to get the stress and deflection down to an acceptable level.

The roof load is what kills. If you could find a way to convert them to trusses as someone else mentioned....it would take a MUCH smaller beam to 30' clearspan for only using a 1-ton hoist. You could actually drop that down to a w10x15 beam for the hoist.

That will be about a 450lb beam vs a 1200lb beam. And will be much cheaper.

Disclaimer: Dont bank on this advise. Its worth what you paid for it. I'm not there, I dont know your roof loads, or any other relevant information. This is just strictly a guess but to give you an idea what you are in for.