Steel Beam sizing

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Old 12-10-04, 01:18 PM
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Exclamation Steel Beam sizing

I have a little project that I could use some suggestions with. It's a very strange deal. I need to figure out how big of a steel beam I need, which will only be holding 10 to 20lb/ft live load. The steel beam will span 25 feet, and it will have no additional loads such as wind or snow. The beam must be no more than 5 1/2" wide, and it can have a maximum deflection of about 1/2" in 25 feet.

My question is how wide this beam needs to be in order to sufficiently meet the above requirements? Basically, the beam needs to be able to hold its own weight when supported on each end without deflecting more than .5". Help!!!
 
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Old 12-10-04, 01:35 PM
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XSleeper,

I would have more questions but to do this right, call your local steel supplier and they may help you out with this. If not, call a structural engineer.

What you are suggesting is a long span and this requires a professionals opinion with facts to back it up. Unsure what this is used for where it is going, they will ask to give you the best advice/recommendations.

Good Luck!
 
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Old 12-10-04, 04:46 PM
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re: Doug

Thanks Doug. The first thing I did was talk to an engineer dealing with wood (LVLs) but he said that steel would be a better option, given the span. When I called our local steel supplier, Norfolk Iron and Metal, they refused to give any suggestions, and also suggested I call an engineer. I visited with a local bridge contractor who deals with I-beams all the time and he seemed to think that an 8" beam would work just fine. Problem is, they weigh 25 lbs per foot! Two 625 lbs I-beams would be a little much for me and 3 other guys to heft up into where we are working.

So i guess my next idea that I'll pursue is whether it would be feasable to use some sort of steel truss. I will be contacting Vulcraft Inc, and will try to speak to an engineer there.

Just to give you an idea of what I'm doing:

Imagine a steel building, which has a 12' insulated ceiling that is sheeted with steel panels. On one end of the building, the guy has framed a few rooms with 8' walls which will be heated. He has put plywood down on top of these rooms so that he has some storage area. (about 3 ft of crawl space above this entire area.)

Well, in one of the rooms, which measures 12' x 32', he has decided that he wants a coffered ceiling. The coffered area will measure 9' x 16'. A short wall will extend up to the finished steel ceiling above.

This guy has no concept of what it takes to accomplish this. He thinks it is simply a matter of cutting off the 2x8 ceiling joists, capping the end with a 2x8x16, building a wall that will extend the coffered area up to the finished ceiling in his steel building, and screwing it together. What he does not realize is that the live load can't be suspended from blocking between the bottom of his trusses. The 18" "soffit" that will be left once the ceiling joists are cut and headed off is just too wide to not have any support. Even though it will only be storage (boxes of file papers), we estimate that there will be about 20lbs of live load per ft.

The 2x8x12 ceiling joists in this room are on 2' centers, and 8 of them must be cut and headed off. To accomplish this, we thought it would be easiest to lay a beam across the "floor" of the crawlspace, and attach each of the cut ceiling joists (below)to this beam in some way (perhaps a custom steel strap).

Anyway, just talking about this with someone will help me immensely. I expect that whatever we do, we will get this guy to sign off any liability, since this whole thing is "his idea". Actually I would like to wash my hands of it all, but that's not possible.
 
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Old 12-10-04, 05:11 PM
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XSleeper,

For that span, would it not be better, if you can incorporate it, is a web floor truss - Look at this link, you may find that you could girder it and it may work just fine. The spans on these are great and can carry that live load easy and more!

I use these allot but I hope I am not misunderstanding what you are wanting to do. You could always e-mail me a sketch to ensure that what I am proposing is not out of line.

http://www.trimjoist.com/spans.html

You may find that your crew can handle these easily.

Hope this helps!
 
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Old 12-10-04, 06:54 PM
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re: Doug

I've worked with webbed floor trusses once... but in this instance, the floor truss would need to sit above part of the load it needs to support. If that would work, then that would be great! Let me have your email. I drew a picture that will help illustrate what I need to do.
 

Last edited by Doug Aleshire; 12-10-04 at 06:59 PM. Reason: No e-mails allowed within posting
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Old 12-10-04, 07:09 PM
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I'm waiting

XSleeper,

I replied to your PM. I'm interested at what you have going on
 
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Old 12-11-04, 07:58 AM
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Thumbs up re: Doug

Doug,

I wanted to thank you for your private messages and even your phone calls in an effort to help me out! After exchanging drawings with you, I think we have come up with an excellent solution, using the web trusses that you mentioned. Thanks again- I'm so glad I found this web site, and ran into someone like you that could help!

When we actually do this project, sometime in January I expect, I will be sure to post the results here, and let you know how it went!

 
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Old 12-11-04, 08:14 AM
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XSleeper,

You're very welcome!

Glad I could provide a quick 3D and 2D drawing for what you need.

Don't be a stranger, we are all here to help each other. We have many topics, moderators and members. Have a question, just ask and and if you can help others, feel free to do so.

Good Luck!
 
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Old 12-11-04, 09:45 AM
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XSleeper and others,

For easy viewing of what was discussed and what was finialized, this link is provided.

http://dougaphs.smugmug.com/Do%20It%20Yourself

Hope this helps!
 
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Old 12-16-04, 11:20 AM
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Exclamation Doug's plan

First, let me say that Doug's plan is a stroke of genius, and that if we followed it to the letter, this coffered ceiling area, and the floor that surrouds it would be beefier than Chef Boyardee.

Now, here is reality: I went to order the materials. I told them what I wanted. 2pc 14" Web truss, 16'9". That was over a week ago. Since then I have had at least 10 discussions with the manager of the local lumber company, who has, in turn, had at least 10 discussions on the phone with his truss supplier. Here is the problem:

I try to order the web trusses. "Subby" calls back and says: "What are they for?" i.e. what sort of load is on them. The load is basically nil. 20 lbs per sq ft max. For some unknown reason, he insists that that is not enough, and that it must be rated at 100 lbs per ft. This "Subby" does not understand what the hell we are doing. I have faxed in everything Doug gave me, to illustrate it. I have reasoned with my local lumber yard manager, and he has even been to see the job site. He feels like he is at the mercy of "Subby" the stupid truss engineer. I wish he would just give me what I ordered.

This is the equivelant of going to the store to buy milk for your kids, and having the grocery clerk tell you that he's not going to sell you milk. he's going to sell you juice. "But I don't want juice, I need milk!" "I don't care, this is what you're getting, because juice has vitamin c." How idiotic.

So, rather than ordering something on the phone that should have taken 1 minute, I feel like I have spent parts of 5 days going around in circles trying to get what I want. In the end, here is what they are willing to send me:

2 web trusses, 27" tall x 16'9" (the entire space between the existing ceiling and the top of the ceiling joists) which will be built like a roof truss, but rectangular, like a web truss.

I am so irritated at these guys, because none of them seem to understand that this thing is NOT going to have that much weight on it. It is purely insane that they are trying to overbuild this as badly as they are. I would love to have Doug get on the phone and ream this Subby.

I am very pleased with the help Doug provided me with, but I've very dismayed that the engineer I have to deal with is such a lunatic.
 

Last edited by Doug Aleshire; 03-28-05 at 07:37 PM.
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Old 12-16-04, 11:37 AM
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XSleeper,

Well thank you very much for the compliment but I am sorry that you are dealing with some pretty stubborn folks.

I think when we talked and what we drew up, was simple in concept and design and will work well for what you needed.

I would have to say that you order what you need and that is all there is to it. They don't need to know what it is for, just that you want a simple 14" Space Joist, Series 320 with a deflection of L/360. No more no less. You sure don't need 27" and it will cost way more. Tell them again and say order them now. This doesn't need a engineers seal and that I assume is what they are trying to determine you need. This is for other purposes and they can have you sign a waiver to release them from liability.

Sorry to hear that the time is being wasted - they should pay you for these delays!

Good Luck!
 
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Old 01-22-05, 04:06 PM
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Thumbs up Finished!

Doug and fellow groupies,

Well, the project went without a hitch, once we finally got our lumber yard to order us something that would work... if you recall from the thread (above), they would not send us what we wanted, and instead they built us 4 trusses (build edgewise, as for a roof) that were 27" wide, and 16'9" long. After sheer nailing them together (so that each pair would work as a unit), we glued and sheer nailed plywood to the face of the truss and down onto the edge of the ceiling below, which had been headed off. My boss took some digital pictures of the project, but getting him to email them to me is another story. If I ever get a copy, I will have to post them here.

Thanks again to Doug who took a personal interest in my project. You were a great help!
 

Last edited by XSleeper; 01-22-05 at 04:08 PM. Reason: typo
  #13  
Old 01-22-05, 04:32 PM
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XSleeper,

That's great!

You're very welcome as well. I'm glad things went well, finally.

Since you have my e-mail address, send the photos when you can. I will place them in my gallery called "Do-It-Yourself" to allow everyone to view.

Thanks for the feedback
 
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Old 03-28-05, 07:05 PM
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Well, all the framing is completed, and here's a couple pictures of how it looked before we covered it all up with sheeting and drywall.

http://pg.photos.yahoo.com/ph/thexsl...e4.jpg&.src=ph

Thanks again Doug!
 
  #15  
Old 03-28-05, 07:10 PM
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Xsleeper,

You're very welcome!

Looks like I drew it! Hope the owner liked it!

Good work!
 
 

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