Ratings for overhead beam for hoist

[TheEquineFencer]

I need to get an idea of what size beam to look for for an overhead hoist. What I had before the fire was a 14 inch web, 1/2 thick and a 7 inch flange beam 30 feet long overhead. What I'm looking at doing now is building a 16 ft. wide mobile hoist. I cannot build it fixed in place using the old anchors I had before because it is sitting right where an arch is for the new steel building frame. The arch is in the way because of an oversight on my part when I ordered the building. Even if it were not in the way I'd still have to do it different because I cannot get the steel beams I used before at the same price, $575. What I had before was built entirely of the 14x7 beams and lagged to the floor on top of a 2ftx2ftx1/2 inch steel plate into a 4ftx4ftx4ft concrete pillar in the floor with rebar. I need to be able to handle a 4000 Lb. load in the center. I've found a 24 ft I-beam, but it has a 22 inch web for $100, but I think that's a little overkill. I'm suppose to be getting another 4000 lb. electric hoist to go back on it. Once I figure out the top beam I'll figure out what I'm going to use for the uprights and such.

 

[gearhead1]

I can calculate it, have stuff to do today, but I can get it this evening. Will send you a PM.

 

[TheEquineFencer]

Thanks.

 

[TheEquineFencer]

bump

 

[BD1]

Wallace Gantry has some info. http://www.wallacecranes.com/thrftste_fixed.htm

 

[Hpozzuoli]

My engineer said I have 1k worth of weight I can put on my hoist. I have only gone up to 500ish. It's a 30ft steel I beam that spans the width of the garage. There is one post in the middle. Not sure if this will help in comparing your situation.

 

[aggierailroad]

So, a 4,000 lb load in the center of a 16 foot span with an A-frame on each end?

 

[TheEquineFencer]

So, a 4,000 lb load in the center of a 16 foot span with an A-frame on each end?

Yes, I need to know what size beam will handle a 4000 pound load in the center of a 16 ft span. It's probably not going to be a true "A " frame, I'll put a support directly under the beam and add bracing.

 

[TheEquineFencer]

Thanks BD1, it looks like I'll shoot for a 10-12 inch beam.

 

[aggierailroad]

A W12x40 simply supported beam on both ends will support a 4.5klb dead load in the center with about an eighth inch deflection.

Use that info how you will and at your own risk. That is the lightest 12" web beam that could safely be used for a dead load. The big driving factor here is buckling due to bending, aka, catastrophic failure. I'm sure the hoist company has some limits on flange size??

 

[TheEquineFencer]

aggierailroad, educate me on beams if you can, W12X40? 12 inch web? what is the 40? 8 inch deflection, meaning with the load it will deflect 8 inches?

 

[readhead]

A W12x40 is 12" tall and 8" wide and weighs 40 pounds a foot. Aggie said 1/8" deflection.

 

[TheEquineFencer]

LOL, I'd just came in and was reading the first post after being outside for a few hours in the sun, I just went back and read it after you pointed it out, thanks. I thought the 40 might be the weight per foot.

 

[MoonRise]

aggierailroad, educate me on beams if you can, W12X40? 12 inch web? what is the 40? 8 inch deflection, meaning with the load it will deflect 8 inches?

eighth inch deflection, not 8 inch deflection.

W12x40 is (approximately) 12 inchs 'deep' (tall) and weighs 40 lb/ft of length.

A bit of google-fu searching for "w12x40" would give you that info as well.

 

[aggierailroad]

One "h" makes quite the difference!

 

[gearhead1]

EquineFencer, I sent a PM. I created an Excel file for you that will allow you to input whatever beam you can find. I do it this way so I can use something that is readily available versus ordering something. I am fairly local to you and can explain if you have questions...

All: FYI, there are 'W' beams and 'S' beams. The W beams have uniform flange thickness where the S beams has thicker flanges. The S beam will have more moment of inertia and is stronger in bending, given the same outer dimensions. The S is also more expensive.

In a nutshell, given the load and a beam size, you calculate the stress in the beam. Then you compare the stress against the yield strength of the material. If the stress is less than the yield strength, then it will not permanently deform. (Some deflection is ok, as long as you're working the beam below the yield strength.) If the stress is higher than the yield strength, the beam will permanently deform, so you pick a bigger beam and repeat the calculation.

 

[TheEquineFencer]

I just sent you an e-mail and a PM. Thanks, this will be a big help. I've found a guy that's about 1-1/2 hours from me that takes down steel structures, mainly bridges of all things. He has a LOT of steel. He has big beams, like in the 16 -48 inch wide size and a lot of smaller stuff. This will make "shopping" with him a lot easier. I think he's looking about 30-40 cents a pound for used steel beams, but again it depends on supply and demand. The last time I looked at steel beams they were around 90 cents a pound new w/o shipping.

 

[Olafur]

EquineFencer, I sent a PM. I created an Excel file for you that will allow you to input whatever beam you can find. I do it this way so I can use something that is readily available versus ordering something. I am fairly local to you and can explain if you have questions...

All: FYI, there are 'W' beams and 'S' beams. The W beams have uniform flange thickness where the S beams has thicker flanges. The S beam will have more moment of inertia and is stronger in bending, given the same outer dimensions. The S is also more expensive.

In a nutshell, given the load and a beam size, you calculate the stress in the beam. Then you compare the stress against the yield strength of the material. If the stress is less than the yield strength, then it will not permanently deform. (Some deflection is ok, as long as you're working the beam below the yield strength.) If the stress is higher than the yield strength, the beam will permanently deform, so you pick a bigger beam and repeat the calculation.

So far, very good but If I have not totally forgot my engineering courses you are not done here. This method leaves no margin for error and without considerations for SWL leaves him with a beam on the verge of collapse under 4000lb load. But I understand this is only the nutshell version.

 

[gearhead1]

You are absolutely correct! I am using a safety factor of two, the spreadsheet I made assumes an 8000lb load. That's from one of my machine design textbooks, Machine Elements in Mechanical Design, Robert Mott, PE.

The other thing is, the I-beam he ends up with might be way bigger than what is required, definitely ok to be safe. The I-beam that can be obtained for $100, though big, might win depending on cost of a smaller one.

I'm happy to send the spreadsheet to you if you want to take a look at it. The last thing we want to do is send someone down the wrong path and they get hurt. I build a lot of my own stuff and am pretty comfortable with my abilities, but I always welcome another pair of eyes - it only makes us better.

On a side note, I am also assuming A36 steel since it is the lowest yield strength I can find for structural shapes. I know the yield strength has increased over the years, but we don't know exactly what material these are that people have lying around.

http://download.capitalism5.com/are-you-properly-specifying-materials-modern-steel-w6351/

 

[gearhead1]

Then the next step is ensure that the vertical supports can withstand the load. We first must consider if it is a column, calculate the slenderness ration, Euler's formula, etc.....

Olafur, do you have access to any FEA software? Just curious....

 

[aggierailroad]

A lot of (including mine) calcs are used under the assumption that it's a point load applied at the centerline of the web - when in fact, a trolley has the forces on wheels on the flanges. That's why I said earlier to check the flange size required by the hoist company.

Hate to see anyone get hurt. FEA for the supports - sheesh - this is getting fun now...

 

[averagehack]

I have recently (still) working through this and to me the real questions are about bracing and whether the ends are pinned or fixed.

In other words, there is a big difference in load carrying (point or otherwise) for any given beam section depending on how the ends are attached (or middle for that matter).

To make matters even more complicated to us non-mechanical engineers, the difference between "pinned" and "Fixed" can be quite subtle.

Long story short, overbuild it and under stress it. Especially if anyone is under it.

Oh...I play an engineer at work but not a mechanical type.

 

[MoonRise]

I have recently (still) working through this and to me the real questions are about bracing and whether the ends are pinned or fixed.

In other words, there is a big difference in load carrying (point or otherwise) for any given beam section depending on how the ends are attached (or middle for that matter).

To make matters even more complicated to us non-mechanical engineers, the difference between "pinned" and "Fixed" can be quite subtle.

Long story short, overbuild it and under stress it. Especially if anyone is under it.

Oh...I play an engineer at work but not a mechanical type.

pssst, just to add more to the 'over-build and under-stress', for 'hoist' stuff with personel on/in/under the hoist/crane/elevator/etc, the required over-build factor (safety factor of actual stress versus material yield stress) changes to 5x or 10x. FYI.

 

[gearhead1]

A lot of (including mine) calcs are used under the assumption that it's a point load applied at the centerline of the web - when in fact, a trolley has the forces on wheels on the flanges. That's why I said earlier to check the flange size required by the hoist company.

Hate to see anyone get hurt. FEA for the supports - sheesh - this is getting fun now...

LOL, I was more concerned about the trolley on the edges of the flanges. What does the flange load look like, will the beam support it, but the flanges just bend at the trolley wheels and the trolley (with the 4000lb load) just drops? Yikes!

 

[gearhead1]

pssst, just to add more to the 'over-build and under-stress', for 'hoist' stuff with personel on/in/under the hoist/crane/elevator/etc, the required over-build factor (safety factor of actual stress versus material yield stress) changes to 5x or 10x. FYI.

The 5X - 10X is good to know! I tried to find a reference, but didn't have one for overhead specifically.

 

[averagehack]

Gearhead -- You are absolutely on the spot! The flange strength is, for me, still a big unknown. Until I understand that I will not be lifting big loads. I may end up, slowly, using empirical methods. Unless someone on GJ can help?

 

[TheEquineFencer]

When I built the last one, just as soon as it was finished I backed the 5600 Ford tractor under it, hooked the 4000 pound electric winch to it and lifted until the winch stalled to test the beam. I figured if that held I was good to go.

 

[gearhead1]

Gearhead -- You are absolutely on the spot! The flange strength is, for me, still a big unknown. Until I understand that I will not be lifting big loads. I may end up, slowly, using empirical methods. Unless someone on GJ can help?

We just need to get someone with access to FEA to do a quick analysis. I wonder if there's a formula in Roarke and Young or another book. I knew an old guy who had a book on loads of plates, like a cylinder head. It was really neat, but that's stuff is probably hard to find with the advent of FEA software

Engineer?

 

[gearhead1]

This is supposed to put the load into the web.

http://www.caldwellinc.com/rig-master/beam-girder-rail-grabs-and-tongs/beam-web-clamp

 

[king nero]

Wheels on flanges are calculated as a point load on a plate that is fixed on three ends. You'll find that in Roark's formulas.
You "just" have to estimate the dimension of the plates you want to use as the beam's flanges.

Oh, and when very near the yield stress, the beam is not "on the verge of collapsing", many beams are calculated plastically (that is, way over the yield stress), which is not a problem if you can live with permanent deformation and with certain restrictions.

 

[TheEquineFencer]

Alright, here's what I've come up with for "parts" so far. I now have a line on (2) 6 inch x 8 inch x .250 thick rectangle post for the uprights, cost $200. They already have 1 inch or 1-1/4 flanges welded to the bottoms and pre-drilled for 3/4 or 1 inch bolts. Now, here's something else I've found. I've found a source of steel I-beams. They are bridge beams from 6-8 inch webs up to 3+ foot webs. The guy has a W14x22 beam, 36 foot long. I realize this is a "light" beam, but will it handle a 4000 pound load at the center point if I span 30-32 feet with it? If this beam will work, I'd be able to span both bays and the end next to my office would loose the "wall clean" as this would take up 8-10 inches out into the shop area. I realize it'll probably flex if side loaded, but I can tie it to the arch of the steel building and take care of that for what I want to do. This guy has a LOT of steel beams.

 

[gearhead1]

How tall are the uprights?

 

[TheEquineFencer]

Right now they are 20 ft tall, I plan to cut them down to 14 foot and cut/weld a steel plate to attach the cross beam to. I just got a call back from the the guy with the beams, I'm meeting him at 1:30 today in Henderson,NC to look at the steel beams he has.

 

[gearhead1]

A W14X22 will buckle, do not use it, even at 16 feet! It is way too light for what you want to do. You need something bigger.

The other thing is if you go the entire length of both bays, adding another 4000 lb load increases the beam size.

What other sizes does he have?

 

[TheEquineFencer]

he has stuff from mild to wild. some is up to 3-4 FEET webbing at over a 100# per foot. I'm leaving in about 30 minutes to go see what he has, it's a 2 hour drive or better one way.

 

[king nero]

A W14X22 will buckle, do not use it, even at 16 feet! It is way too light for what you want to do.

Why will it buckle?
when the load is on the bottom flanges, where exactly will it buckle?

I haven't run the calcs (as I've only got european programmed spreadsheets), but it does sound like within limits.

 

[TheEquineFencer]

OK, I went and looked at what the guy had. He has some impressive steel, but with just as impressive prices. The W14x22 36 ft long I went to look at wasn't there. It was in Mt. Airy, 3 hours away. What he did have was an impressive 33 ft beam for $1200.00. The W14x22 he wanted $350 for it. I called Dillon Supply in Goldsboro and was given a verbal quote of $485 for a W14x22 35 ft long dropped off at our shop. I need 32-33 ft to span both bays. This other guy is about 2 hours or more way at just over 100 miles away. Translation; $100 worth of fuel to go get abeam that's not there. If it were there, I'd have $350 in the beam and $100 in fuel, not counting my time, I'd have $450.00 in a beam that for $35 more I could have a new one that doesn't need cleaning and painting. I just got a text from a guy with what is either a W16x26 or a W16x31 that's 22 foot long. I may end up using that one and putting a 2x6x20 "C" channel cap on top of it and build a roll around hoist. I've got to come up with the metals for the legs at the bottom of the uprights. Northern Toll has the wheels I'd use. They have some in the 1000# -1200# pound range. I'd put three under each side of the uprights. I've got to do some figuring on beam sizes and such. I'd like to stay at 14 foot open area under the hoist. right now my shop lights are at 15 feet to the floor. I could raise hem some without a lot of trouble. The reason for the 14 ft limit is so I can have a margin of error if I drive or back a road tractor or trailer in the the shop. 13 ft 6 inches is a normal max height for them.