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jfpenkala · May 4, 2014, 10:06 PM

I am looking for advice on what size steel I-Beam I need for a particular application. I need a beam to span 23ft supported only at the ends. From the center of that beam will hang a 400lb static load via a Rated Beam Clamp. I would normally use 12x12 aluminum tubular truss for this application but space is limited. Therefore, I am looking for the smallest I-Beam that will give me a safety factor of 5+. Any help will be appreciated.

JP

ebaines · May 5, 2014, 06:28 AM

Define what you mean by "smallest" I-beam - do you mean overall height of the beam? Or do you mean lightest weight? Also, do you have any constraints on max deflection of the beam? It's quite common that while an I-beam may be strong enough to hold the weight, it may deflect more than you want, so let us know if that is a concern.

talaniman · May 5, 2014, 07:14 AM

https://www.gorbel.com/pdfs/Jib%20Brochure/Gantry.pdf or Steel Beam Calculator | Run Calculation

One of these should help, and consider the use of portable supports.

http://www.bing.com/images/search?q=...&FORM=IQFRML#a

Depends on your application, but gives a greater range of I beam sizing options, and enhances safety ratings cheaply, by reducing deflection, and mitigates lengthy run/weight restrictions. A standard tool for most construction crews replacing faulty/damaged load bearing beams either steel or wood.

What are you looking to lift?

jfpenkala · May 5, 2014, 07:18 AM

ebaines, Thanks for the reply! Yes, when I said smallest what I meant was that would like the overall height and weight of the beam to be minimal. I don't think that a little deflection would cause concern. I have about 5-6 inches of clearance. However, my main priority is safety. If it has to be bigger and heavier I will use it. Most of the hardware I use has a 5x - 10x safety factor. This is the first time I've had to look into something "structural" because my normal "tools" don't fit the application. Thanks again for your help.

JP

ebaines · May 5, 2014, 07:57 AM

Originally Posted by jfpenkala

Yes, when I said smallest what I meant was that would like the overall height and weight of the beam to be minimal

Well, which is it - height or weight should be minimal? Don't say both - generally a less tall I-beam will require larger flanges and the overall weight of material is increased over the weight of a taller I-beam. Also, are you suggesting that a 5" tall I-beam is the max you can use?

jfpenkala · May 5, 2014, 08:03 AM

Originally Posted by ebaines

Well, which is it - height or weight should be minimal? Don't say both - generally a less tall I-beam will require larger flanges and the overall weight of material is increased over the weight of a taller I-beam. Also, are you suggesting that a 5" tall I-beam is the max you can use?

Height is my real limitation. I know I have at least 5". 6" might fit but I won't be able to confirm this anytime soon. Let's assume 5" is max height.

jfpenkala · May 5, 2014, 08:20 AM

Originally Posted by talaniman

https://www.gorbel.com/pdfs/Jib%20Brochure/Gantry.pdf or Steel Beam Calculator | Run Calculation

One of these should help, and consider the use of portable supports.

portable I beam support jacks - Bing Images

Depends on your application, but gives a greater range of I beam sizing options, and enhances safety ratings cheaply, by reducing deflection, and mitigates lengthy run/weight restrictions. A standard tool for most construction crews replacing faulty/damaged load bearing beams either steel or wood.

What are you looking to lift?

I will be hanging 2 large loudspeakers from it. The actual weight is about 330lbs. That includes the rated fly-ware truss modules attached to the speakers.

ebaines · May 5, 2014, 09:22 AM

I strongly suggest that you engage a professional engineer to check this, but a S5x10 steel I beam would do it - it's 5" tall and 3" wide, and its weight is 10 lb/ft. or 230 pounds total. Supporting a 400 pound weight at midpsan plus taking into account dead load of the beam itself gives a safety factor of 4.98. Deflection is minimal - about 0.67 inches.

Be careful on how you plan to attach the weight to the beam - it would be best to suspend the weight from the bottom flange, as opposed to using a cable over the top of the beam. Otherwise I'd be concerned that with a relatively skinny beam like this it may twist. Also be sure that the ends of the beam are securely attached to the supporting columns so that the beam can't fall over on its side.

jfpenkala · May 5, 2014, 09:59 AM

Originally Posted by ebaines

I strongly suggest that you engage a professional engineer to check this, but a S5x10 steel I beam would do it - it's 5" tall and 3" wide, and its weight is 10 lb/ft. or 230 pounds total. Supporting a 400 pound weight at midpsan plus taking into account dead load of the beam itself gives a safety factor of 4.98. Deflection is minimal - about 0.67 inches.

Be careful on how you plan to attach the weight to the beam - it would be best to suspend the weight from the bottom flange, as opposed to using a cable over the top of the beam. Otherwise I'd be concerned that with a relatively skinny beam like this it may twist. Also be sure that the ends of the beam are securely attached to the supporting columns so that the beam can't fall over on its side.

Understood. I will have the numbers verified. I was concerned about twist or roll as well. Therefore, I am planning to use a 1-ton beam clamp attached to the bottom flange.

talaniman · May 5, 2014, 10:13 AM

Originally Posted by jfpenkala

I will be hanging 2 large loudspeakers from it. The actual weight is about 330lbs. That includes the rated fly-ware truss modules attached to the speakers.

Thanks for the clarification, lifting was my wrong assumption, but leads to the question of two loudspeakers suspended or mounted in the middle of a garage. You lose much acoustic value it would seem if the speakers are together as opposed to apart. These are loudspeakers for music I assume.

ebaines · May 5, 2014, 10:14 AM

How do you plan to secure the beam at the ends to keep it from falling over? I could imagine people doing things like leaning a ladder up against it, creating a side load that could cause it to tip over.

jfpenkala · May 5, 2014, 11:24 AM

Originally Posted by talaniman

Thanks for the clarification, lifting was my wrong assumption, but leads to the question of two loudspeakers suspended or mounted in the middle of a garage. You lose much acoustic value it would seem if the speakers are together as opposed to apart. These are loudspeakers for music I assume.

Actually, the idea is to cover the audience with the direct sound from the loudspeakers. In this long, narrow room a left - right deployment puts too much sound on the walls. The sound reflects off the walls and interferes with the direct sound.

jfpenkala · May 5, 2014, 11:28 AM

Originally Posted by ebaines

How do you plan to secure the beam at the ends to keep it from falling over? I could imagine people doing things like leaning a ladder up against it, creating a side load that could cause it to tip over.

I am using either a Beam Clamp Fast-Fit or GirderFix. It's a 90 degree install so it will most likely be a GirderFix.

http://beamclamp.com/connection-solu...tail/girderfix