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Up Topic Welding Industry / General Welding Discussion / Engineering question
- - By Joe Davidson (**) Date 01-10-2010 04:24
I hope to hear from some engineers on this. I am installing an I-beam in my shop to lift stuff off my truck, like my sa-200. I asked an engineer at a shop were I used to work, he told me the beam would deflect 3/4" with 1500#'s on it. It is a 8" wide flange beam, actual dimensions are web: 8 1/2" tall, 1/4" thick, flanges are 5 1/2" wide and 1/2" thick. It will be 13' long and supported on each end with a 1/4" x 5" square tube. I have seen guys lift some heavy stuff with 3" pipe "A" frames and it didn't look like it was deflecting that much.  Just curious if I am going to be able to use this beam for what I really want it for.
Parent - By MBSims (****) Date 01-10-2010 05:07
For the dimensions you have, the closest standard shape I can find is a W10 x 26, which has a section moment of inertia of 144 in^4.  Supported at both ends with 1500 lbs. in the center, the deflection I come up with is 0.029 inches.  That is using a calculator at:

http://www.engineersedge.com/beam_bending/calculators_protected/beam_deflection_2.htm

I'll have to calculate the cross section moment of inertia for your beam and check it by hand to be sure.
Parent - - By RonG (****) Date 01-10-2010 14:22 Edited 01-10-2010 14:25
Joe, I am not sure how you intend to apply the load. You say "supported on each end with a 1/4" x 5" square tube" so I assume you will not be useing it like boom.

That being said, I should think one would need to know the area (lenght) along the beam the load will be applied as well as distance from the up rights.

Just a thought but if you (assumeing you will be useing a trolly) you can make it wider and spread the load out over a greater distance to effect the deflection.
Parent - - By Joe Davidson (**) Date 01-10-2010 17:22
I will be lifting straight in the center. Not planning on moving the load when it is on the beam. I have plenty of rollers to move stuff around once I lower it to the floor. mainly just want to be able to get welder off truck without having to go to my buddies and use his bobcat. Just mainly wanting to make sure it will support the welder long enough to pull truck out and lower it. Thanks Joe
Parent - By RonG (****) Date 01-11-2010 03:18
MBSims called it pretty close although I figured it to be less than half that. If you just throw a line (sling, choker or chain over the beem you will see the greatest deflection verus useing something to spread the load out over wider area. Doing that I do not belive you could even measure it.

Point being, the beam will handle the load with no problem. I have seen smaller beams on jib hoist with a Ton & 1/2  chain fall.
Parent - By waccobird (****) Date 01-11-2010 10:45
Joe Davidson
The beam you speak of is a Wide Flange Beam W8X21.
Not really enough information to your design for the best answers to your question.
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or just plain

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Excuse the stick figures but to work I must go.
Good Luck
Marshall
Parent - - By uphill (***) Date 01-11-2010 11:32
Not being an engineer but I doubt it would deflect that much if the beam was 20 feet long. I have a heavy 5" I-beam in my garage it has a 1/2 ton hoist with a 1 ton trolley thats 14" long supported on one end by a 3" sched 40 pipe tyed to the rafters so it cant move. The other end is a 10" shed 80 made into an air tank/ engine stand combo bolted to the floor. Being strapped for smarts once and a while it has picked up considerably more with less deflection. I have a tattle tail 1/16" cable strung tight 1/2" off the back edge so I can know when its time to rethink my project.

Your application sounds very safe, I would venture to say it would pick 3-4 times your target load before it moved that much.

   Uphill
Parent - By Joe Davidson (**) Date 01-12-2010 03:34
Thanks guys, I feel confident it will work out fine.
Parent - - By hotrodtodd (**) Date 01-12-2010 03:39
i use a regular engine hoist/ cherry picker to remove my 300d off my truck all the time never any problems dont need anything as big as your planning
Parent - By Bob Garner (***) Date 01-12-2010 19:05
I like Uphill's use of a tattle tale to indicate if things are deflecting too much.  But, before you listen to me, I'm the kid who strung a come-along on my garage roof beam to lift a buick nail head to install in my old Ford.  I hooked her up and started ratcheting.  Everything looked O.K. so I kept on ratcheting.  Still no problems so I kept it up.  Hey, wait a minute, this engine ain't goin' nowhere.  So I looks up - at a roof beam bowing a good six inches in the middle and an engine that is barely off it's mounts.

Keep your deflection to less than the span divided by 240 (360 to be conservative) and you should be O.K.
Parent - - By boiler tube (*) Date 01-13-2010 00:59
Hey, Joe
You may want to check out the websites of gantry crane manufacturers like wallace. You can get beam sizes for different span and capacities
Parent - By Joe Davidson (**) Date 01-13-2010 05:07
Thanks for all the responses. It lifted  the welder, and never moved. Not that I could measure with a tape measure anyway. I appreciate all the feedback from you guys. Great site for anything and everything a guy might need. Thanks again. JOE
Up Topic Welding Industry / General Welding Discussion / Engineering question

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