structural question

[gordfraser]

i have to make a 9' long (span) trolley hoist in a building.
the most to be lifted = 600#
trolley is rated for 1000#

lets call the max mid way load 1000# for a safety factor.

what size i beam should i install?

thanks

[Donald Branscom]

i have to make a 9' long (span) trolley hoist in a building.
the most to be lifted = 600#
trolley is rated for 1000#

lets call the max mid way load 1000# for a safety factor.

what size i beam should i install?

thanks

It would be easy to figure this out.
Just go on line and look at pre made trolly cranes and they are all ready engineered for your requirements. For instance....http://www.globalspec.com/industrial-directory/crane_trolley

[gordfraser]

Donald.
Great idea. But a bad link. Register to go anywhere in that site.

I did a lot of googling and only came up with tables that I could not use.
I'm not an engineer.

[BlauSchuh]

Donald.
Great idea. But a bad link. Register to go anywhere in that site.

I did a lot of googling and only came up with tables that I could not use.
I'm not an engineer.

this place recommend a 5:1 safety factor...

http://www.cmworks.com/Public/7662/BridgeKit_Man.pdf

you're looking at an i beam with a 7" flange and a 15+" height... i spent all of 5 second looking at the pdf so youll want to verify this applies to your application

[BlauSchuh]

Here's another coupe of links
http://www.hoistsdirect.com/vestil_cranes.htm

http://www.hoistsdirect.com/wallace_gantry_cranes.htm <= This one calls for a 8" or 10" I beam depth for a 10' span, with a load rating of 2 Tons.

[tenpins]

this place recommend a 5:1 safety factor...

http://www.cmworks.com/Public/7662/BridgeKit_Man.pdf

you're looking at an i beam with a 7" flange and a 15+" height... i spent all of 5 second looking at the pdf so youll want to verify this applies to your application

OSHA requires a minimum 5:1 safety factor for all rigging. 10:1 if you are hoisting personnel. Maybe OSHA has no auspice on this crane if its private or not otherwise for commerce. So keep in mind a minimum 5:1 safety factor is the industry standard.

If the trolley is rated for a grand, and that is from a reputable manufacturer, it is safe to assume that the breaking strength is at least 5 grand. 5 grand aint that much really when you are talking about kN. Look at some of the paltry, albeit rated for 5 grand, connections in a personal fall arrest system.

[Donald Branscom]

Donald.
Great idea. But a bad link. Register to go anywhere in that site.

I did a lot of googling and only came up with tables that I could not use.
I'm not an engineer.

I did not mean for you to look up tables, but rather look up trolly cranes they sell and their ratings, and from the size given you can read the specifications and see what size beam they are using and then either buy a trolly beam the correct size or buy one of their kits.
One of their portable trolly cranes actually stated the beam size and thickness. See what I mean?

[Fat Bastard]

He could just hire an engineer to tell him what size and shapes will do the work required.

Or ask a bunch of strangers in a open forum how to keep from killing himself and others.


Strange new world.

[LawsonWeldingLLC]

just use 2x4's and gorilla glue, itll hold.

[gordfraser]

Thanks to all who were helpful.
i did some googling on this subject, but it didnt seem to be by luck google day.

FB and Lawson are excluded from the thanks as they seemed had nothing better to do but troll.
who knows. someday i might just find your bridge.

[Fat Bastard]

Bite me.

[forhire]

Gord,

You need to decide how much deflection is acceptable in your application and then do some math. This might be enough to get you started: http://www.submarineboat.com/gantry.htm

Looking at commercial gantry cranes can be helpful and woefully dangerous at the same time. You do not know what grade of steel is under the paint or what processes the beam went through to meet the manufacturers specifications. I have some commercial cranes that use some deceptively small material.

Your span and lifting requirements are minimal. It's your shop. Do the math, scrounge up some material, and post the pictures when your done.

You can buy some engineered plans here:
http://www.synthx.com/shop/product_info.php?products_id=4

[LawsonWeldingLLC]

Sheesh , just tryin to lift the mood lol

[CEP]

This should help, from a gantry crane website.

[millrat]

Also keep in mind that your "load" includes the weight of the trolly and lifting device (chainhoist, come-along, other rigging, etc.) The structure where the beam is landed also needs to be considered for loads.

[red dog]

Hi Gord...I just went through the same exercise. I have a 1000 lb trolley and a span of 14'. I asked an engineer friend of mine what I would need to support a midway load of 1000 lb., and would a 6" I-beam do the job. He said it was more than enough. I never did ask him what it was capable of supporting, but I suspect it was much more. In any case, my trolley specs were my limiting factor. I just wanted to be able to lift generator, welder, mower, table saw, etc., since I've come to an age where I don't think it wise to continue slinging those things onto the back of my truck by hand.

The 6" beam was 14' long and a W6 X 15 beam (that's a Wide beam, 6" web at 15 lb per foot). That's 6" x 6" flange (not an S beam which is 6" x 3.33" flange). The main difference in the beams is that the flange on the W beam is flat, where the one on the S (Standard I-beam) is tapered. Some trolleys will run on a tapered beam with tapered wheels and also on a flat flange in some cases, but run better on the flat flange of a W beam.

FYI, I supported it with a 4" beam on each end, with a strap welded to the top to attach to joists above to support it fore and aft at the top and a plate 5"x10" on the bottom, drilled for concrete anchors on the floor. I've lifted 600 lb with NO deflection at the midpoint of the 6" beam.

My weak link in this whole setup is the trolley and the chain hoist, which are both rated for 1000 lb. Good luck......Don Fraser

[forhire]

This should help, from a gantry crane website.

I am not an engineer. :dizzy: I've looked at these tables and the dimensions appear to be similar to normal S beams. I wanted to do the math to make sure they hadn't heat treated and/or engineered a custom shape. Tables can be a good guide but I prefer to check the math.

For example, if I take the first span, 10' span 5" high by 3" wide... it looks similar to an S5x10. When I do a 2000 lb static center load calculation on this beam... I'm getting 0.20" of deflection. This is exactly at span/600 (span divided by 600) which is standard for crane girders. In this case it would appear they are using standard shapes.

The 6" beam was 14' long and a W6 X 15 beam (that's a Wide beam, 6" web at 15 lb per foot).

For fun I plugged in Don's values. At 1000 lbs you should expect about 0.12" of deflection. At 600 lbs you would have experienced about 0.0702" of deflection... not enough to notice. :D Assuming your maximum deflection would be 0.28" (168"/600) this would place your maximum safe load as 2400 lbs. :D

[forhire]

i have to make a 9' long (span) trolley hoist in a building.
the most to be lifted = 600#
trolley is rated for 1000#

lets call the max mid way load 1000# for a safety factor.

what size i beam should i install?

Your maximum deflection should 0.18" (108"/600). An S4 x 7.7 lb/foot (4"x2.663") is right close... it will give you 1200 lbs with 0.18" deflection (0.0893" at 600lbs). Most the wide shapes will do nearly double that at that span.

My 1 ton by 10' span gantry uses W5x19 beam.

[red dog]

I am not an engineer. :dizzy: I've looked at these tables and the
For fun I plugged in Don's values. At 1000 lbs you should expect about 0.12" of deflection. At 600 lbs you would have experienced about 0.0702" of deflection... not enough to notice. :D Assuming your maximum deflection would be 0.28" (168"/600) this would place your maximum safe load as 2400 lbs. :D

Thanks for the info FORHIRE....2400lb.....I will never use it for that kind of load, but it's good to know what it's limits are :waving:

[weldin rod]

I agree with lawson, Just throw her up there with some gorilla glue and 2x4's, add a couple of come alongs or something if you have to. She'll hold.

But seriously, I'd consult an engineer.

[Donald Branscom]

Gord,

You need to decide how much deflection is acceptable in your application and then do some math. This might be enough to get you started: http://www.submarineboat.com/gantry.htm

Looking at commercial gantry cranes can be helpful and woefully dangerous at the same time. You do not know what grade of steel is under the paint or what processes the beam went through to meet the manufacturers specifications. I have some commercial cranes that use some deceptively small material.

Your span and lifting requirements are minimal. It's your shop. Do the math, scrounge up some material, and post the pictures when your done.

You can buy some engineered plans here:
http://www.synthx.com/shop/product_info.php?products_id=4

If you watched that video please do not use a 5/16 bolt on a 3/8 chain. Use a shackle rated for the purpose!! And was the bolt a cheap hardware store bolt!!! yikes!!!

[Groo]

If you watched that video please do not use a 5/16 bolt on a 3/8 chain. Use a shackle rated for the purpose!! And was the bolt a cheap hardware store bolt!!! yikes!!!

that is why you need a safety factor. stuff breaks or slips and you get a shock load.