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Old 06-11-2011, 04:55 PM   #1
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structural beams


what will the weight and size for a steel beam or wood for a span of 48'. looking to install two beams to carry the floor of 30 '
Will be used to create open space no intermidiate colums?
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Old 06-11-2011, 05:17 PM   #2
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Astronomical!

That kind of information can only be obtained from an engineer. You are talking about some long spans, that will require very big, very heavy steel. Proper footings will also be quite large.

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Old 06-12-2011, 02:04 AM   #3
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My steel reference book shows, for ex, a 16" x 11.5" wide flange beam, 88 lbs/ft, carrying a uniform load of 50,500 lbs with a maximum deflection of 3.58". You can do about the same with a 21" x 8.25" WF at a mere 73 lbs/ft, too. As stated, see an engineer.
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Old 05-01-2012, 11:55 AM   #4
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For my current addition project I am using a slightly shorter span than the one you want.

If you don't mind, I would like to ask JKlingel if there are any people on here who *are* able to help us navigate the W-Beam ratings, BEFORE we go to an engineer for a final approval.

I don't mean to come off as irreverent here, but if we can put a man on the moon, seems to me there must be an outside chance that some DIYers have probably found some kind of table that would simplify all the mathematical complexities.

Heck even when I did go and see an engineer on my first design (which used 1 support post under a 35' span), even HE relied on a software program.

Hey, I'm a newbie too. And I hate to be the bearer of bad news but what I can tell you is - as far as I know, steel suppliers have to special order anything longer than 40 feet.
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Old 05-01-2012, 05:43 PM   #5
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Originally Posted by LedgeVictim View Post
For my current addition project I am using a slightly shorter span than the one you want.

If you don't mind, I would like to ask JKlingel if there are any people on here who *are* able to help us navigate the W-Beam ratings, BEFORE we go to an engineer for a final approval.

I don't mean to come off as irreverent here, but if we can put a man on the moon, seems to me there must be an outside chance that some DIYers have probably found some kind of table that would simplify all the mathematical complexities.

Heck even when I did go and see an engineer on my first design (which used 1 support post under a 35' span), even HE relied on a software program.

Hey, I'm a newbie too. And I hate to be the bearer of bad news but what I can tell you is - as far as I know, steel suppliers have to special order anything longer than 40 feet.
There are too many variables for anyone to rightfully size any support online. Even if you were told the size of the beam by someone here, how can it be trusted when they have not seen the site? When the span is increased, the point loads have to go somewhere. That's what the engineer is for. They take responsibility for the new design after they accounted for the site variables, that's why they cost so much.
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Old 05-01-2012, 08:52 PM   #6
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Sure....you can get someone to give you a ball park figure on the beam.....but without engineering, you will not get a permit, much less approval from the inspector.

I can understand why ledge is asking a similar quesiton....I think we all like to have some idea of what it will be and if it is even possible. I can see the logic of avoiding a trip to the engineer if what your wanting to do is unreasonable.

The answer to that is picking an engineer who is also an architect. Like the one I used. He swung a hammer before he got into his current profession....so he knows what works and what does not.

Lets be honest....if your looking to go that big of a span....you should not be complaining about the small amount your going to pay an architect/engineer.
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Old 05-01-2012, 10:57 PM   #7
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Quote:
Originally Posted by LedgeVictim View Post
If you don't mind, I would like to ask JKlingel if there are any people on here who *are* able to help us navigate the W-Beam ratings, BEFORE we go to an engineer for a final approval.
OK, you asked, so here is my opinion. I don't think anyone who is concerned with your safety and their butts will take a stab at this online. Dan Holzman is an engineer here, so you may get a reply from him. You can find engineering-type books at the library, and/or ask at a steel yard. I think you may be talking truss more than beam.
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Old 05-02-2012, 12:51 AM   #8
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Well, you can find plenty of beam calculators online. Start by Googling... I don't know... "beam calculator". I use a paid product, BeamChek, which you can buy for life for $150 (no annual fees)! It's a great program.

But the point is made above: unless you know what you're doing, you are more likely to get the wrong answer than the right one: too little (someone dies) or too big (waste money/other trade-offs). And for permitting a structure like you're mentioning, you will almost certainly need a PE sign-off anyway.

Nonetheless, I find the software to be profoundly helpful: I can run scenarios as I'm thinking about something, check on pre-existing framing, etc. It's quite useful. Of course, $150 may not seem reasonable for a DIYer.

Note that there are lots of other elements to safe building (footings, posts, bearing surfaces, lots of stuff), and the stakes all increase at these big spans. I strongly recommend not being an idiot.
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Old 05-02-2012, 09:14 AM   #9
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casey2u – Thanks for the BeamChek suggestion.
jklingel – Thanks for those tips. In my introduction to this site I only barely mention that I got my first plan (prior to ledge removal adventure) approved by a semi-retired engineer. Any assumption – by anybody here - that – because I’m inclined to spec the beam myself, that I must be trying to sacrifice safety to save money – is a little below the belt.

I find it interesting that the replies to this thread so far, while intonated nicely enough, still opted to hum the mantra of licensed SE’s and architects being required, for every smallest material that needs to be costed out.

My award winning engineer is retiring this year. His wife is dying. He did my first approval at no cost. Money means little to him at this stage. I am merely trying to do the homework. (Unlike anyone who never passed a course in Algebra. (wags head toward Joe Carola).

Last edited by LedgeVictim; 05-02-2012 at 09:15 AM. Reason: addendum
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Old 05-02-2012, 10:15 AM   #10
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Chill out Ledge. The OPS, whose thread you hijacked, never asked the "typical length" of a wide flange beam. He wanted to know what size a steel or wood beam needed to be to span 48 feet.

As others have pointed out, this is far from a simple question, and as a registered professional engineer with a license at stake, I stay far away from answering complex design questions over the internet from someone with whom I have no contract, at a site I have never seen, and for an unknown application.

As for the concept that you can substitute a table for knowledge, or perhaps grab a low cost or free on line calculator and do structural analysis, this can certainly work for simple problems, and is especially useful for repetitive analysis of similar problems like uniformly loaded beam design. The hard part is correctly calculating all the loads, their point of application, and potential failure mechanisms. That is not so simple or obvious, and for a 48 foot long beam, is essential.
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Old 05-02-2012, 11:03 AM   #11
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Daniel,

I would prefer to not abuse the OPS’s thread any more than you would.

I will be posting my own by this evening hopefully.

Any final approval and permitting for a building is ultimately made on the entire composite, is it not? Provided you had the drawing in front of you, and I ended up with a deflection in the beam that neither of us could approve, what would you do next if you owned your own architectural firm?

Suppose a necessary 2 inch elevation change for the proper beam unattractively altered the final profile. Would you throw in complimentary drafting time, or would you charge another $600 for some intern to tweak my AutoCAD dwg for an hour?

Just askin’
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Old 05-02-2012, 11:50 AM   #12
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Originally Posted by LedgeVictim View Post
Suppose a necessary 2 inch elevation change for the proper beam unattractively altered the final profile. Would you throw in complimentary drafting time, or would you charge another $600 for some intern to tweak my AutoCAD dwg for an hour?

Just askiní
I'm not quite sure what you're "just askin'"... Often, design has to be an iterative process with structural analysis beginning from an early stage. If you get to final drawings or permitting and discovered that you had the wrong beam size... something went wrong in the process a while back. That IS the danger of recommending BeamChek, for example: someone who doesn't know how to calculate the loads does it wrong, proceeds with the rest of their plan development, and then tries to get an engineer to stamp them, only to discover a major redesign is required.

On the other hand, I DID recommend BeamChek b/c it can be useful to someone who takes the time... with the caveat that they are still more likely to screw up than a licensed engineer (who also has some chance of screwing up).

I don't understand from your question why the structural engineer would bear blame.
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Old 05-02-2012, 12:17 PM   #13
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I'm still wondering why there is this avoidance of even kindly providing the OPS with any information as to whether his/her beam dream would cost $500 or $8000.

It seems to me you could safely provide that much information to the OPS.

Why the rush to play with me instead? I already stated I have not intention of end-running any part of the approval procedure. I am merely looking for a website or two that would help one to even navigate the various formulas if they existed. I am not asking anyone to "run" those formulas without reliable data or any data at all. C'mon.

For the approval of my first plan, I drove the 120 miles for the face to face. The engineer and I spent a tedious hour discussing all the intended live loads. After that it took him all of 5 minutes on his computer to find that I'd estimated the correct size. In that case, a single 36' beam was to be pinned at each end and also bear upon one asymmetrically positioned support column.

In the new design I will be pre-specifying (share the simple 900ft^2 load over) TWO (2) beams.

If there are no standard tables available out there for the normal deflection of various unloaded spans and weights of these beams (as a starting point), I would be highly suspicious as to the reasoning. I suppose that, considering liability issues, there likely are scores of people out there who are stupid or indigent enough to do a design change and implement it, on the basis of an earlier building permit, without going back for a new approval. But I am not one of them.

Hope we can discuss this more at length on my own thread once it is posted.

Shame on us all if you Daniel own the appropriate software and still won't offer a less stuffy reply than that, even after someone told you their design had come in with an L360 load or whatever you needed to have for data. In my case the search is for a preliminary guesstimate for establishing a critical elevation for crying out loud.

And even if a simple beam needed to be a welded truss instead, then presumably you would be informed enough to point me or anyone in that direction.

Er, presumably.

Shrug.
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Old 05-02-2012, 12:35 PM   #14
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casey2u,

Daniel is technically correct about "us" jacking this thread. Although it would likely make a well-appreciated read, even to Abie him/herself.

I entirely get what you guys are saying.

My core gripe - at this moment - thanks to all for the buzzkill - is probably the apparent charade on here, that engineers and architects still perform each and every calculation while locked away in a sound deprivation chamber with a slide rule.

You guys are killing me here.

If I tilt the engineer/architects' pro-bono meter(s) dorkily enough, then I will likely burn the bucks intended for the car lift for which the beam was necessary in the first place.

I dunno. Maybe all of you are working with 3" thick yellow pages.

Mine is 7/16" and spans two states.
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Old 05-02-2012, 12:59 PM   #15
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If I get a chance, by tonight, on my own thread, not on this one, I may include a question or two about one possible alternative I have.

I rather suspect I could afford, and more importantly "FIT" a W18 in place of the currently solid drawn W16. I'd merely lose a little headroom at the walls in the attic/storage area. Based on 2x8 rafters, which might be overkill for all I know.

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