I Beam Span Requriements

[SundownIII]

As most know, I am a registered professional engineer, and have been for nearly 35 yrs.

I'm not going to tell the OP what I beam to use since we're talking lifting loads and I obviously don't know enough about the total project to do so.

What I will say is that Mr McCormick has proven himself an idiot beyond question. He often times comes up with some pretty far out stuff, but he really went overboard with his comments here. His distaste for qualified engineers is likely because they have proven him to be a fool on numerous occasions. I wouldn't put any stock in anything he says.

Actually, as has been pointed out, there are simple references available to calculate the I-beam (or several options) required to support the stated load. The calculation is really very simple. Believe it or not, it's not rocket science.

You're going to find that most of the recommendations stated in this post are gross overkill. (and I'm talking about by a factor of x 10 atleast). 1000# is not much load. Other than the fact that an I-Beam lends itself well to a trolly type system, this load capacity could easily be achieved with a wooden truss beam which would be considerably cheaper than an I-Beam. 10'span and 1000# load. No big thing.

To the OP:

You may want to check out Northern's fixed height gantry cranes. They use a 3" W x 5" H I Beam to achieve a 2000# rated capacity over 10'.

[William McCormick Jr]

I have seen chain hoists of old and new. And the old ones, also designed by engineers, were often twice as large, and the chain is two to four times as large, on the older models. If my life depended on it no doubt I want the big one. I have seen and heard the smaller newer ones, bend under a load.

I have seen the old elevator chain, for lifting very small lightweight freight elevators and that chain is massive compared to what would be said to carry ten or twenty times the load safely today.

I see the stuff coming down around me at work. I see the depth of embedment in stone, going from 12" to 8" to 6" to 2 1/2"".
Designed and approved by architects, engineers, and building boards.

Now you might say that 12" embedment is a gross overkill, you will be standing with most of your engineering buddies on that. And you are right compared to 2 1/2" it is a gross overkill. But that thinking is what leads to 2 1/2" embedments.

But I learned that cement is an aggregate with zero engineering value, from a team of highly trained engineers. Yet we see things like this today below. Designed by modern engineers. Been told it is totally safe, totally effective. It started cracking before they finished the top floors. They stopped the job.

http://www.rockwelder.com/government/cement1.jpg

Cements definition is an aggregate, not a structural material. Just because the Germans made bomb resistant bunkers in a hurry with this method of building. Does not mean it is safe or an engineering material. It just means they heaped it on in a hurry and it held up well. In that particular place in that particular design for an emergency. Usually in dome shapes so there was no possible pulling force upon it. Only compression forces. Because that is what an aggregate is for compression. Not adhesion or pulling.

The term glutinous means of the nature of resembling, glue; sticky. The term cement means any glutenous adhesive substance which serves to unite bodies. To become solid.

I don't know if you have ever gotten close enough to the job site to see what actually goes on with cement or road aggregate.
But they basically heap it together, a little more, a little less watery, a little more or less settled. A little more or less cold or hot, a little more or less tampered, or finished. A little thicker here then there. A different color here then there. One area sets up very fast in the sun the other very slow in the shade. One spot settles up slow and the other fast both spots in the sun. One spot settles up slow the other fast while both are in the shade. One batch has rocks, the other does not.

This is why you are calling it engineering. Because you think you have engineering materials. You have aggregate. A sum of stuff heaped together. There is wood, leaves, paper, plastic, cigars cigarette filters, urine, cat, dog, and human, in the mix. You name it I have seen it.

On a side note, we were given permission to core out six inch cores in the cement for the risers. Because they altered the plan to save money on placing forms. Right next to the support columns, I was coring through two inch rebar. Hundreds of holes on each floor.

Maybe that is engineering?


Sincerely,


William McCormick

[mot krig]

As most know, I am a registered professional engineer, and have been for nearly 35 yrs.

I'm not going to tell the OP what I beam to use since we're talking lifting loads and I obviously don't know enough about the total project to do so.

What I will say is that Mr McCormick has proven himself an idiot beyond question. He often times comes up with some pretty far out stuff, but he really went overboard with his comments here. His distaste for qualified engineers is likely because they have proven him to be a fool on numerous occasions. I wouldn't put any stock in anything he says.

Actually, as has been pointed out, there are simple references available to calculate the I-beam (or several options) required to support the stated load. The calculation is really very simple. Believe it or not, it's not rocket science.

You're going to find that most of the recommendations stated in this post are gross overkill. (and I'm talking about by a factor of x 10 atleast). 1000# is not much load. Other than the fact that an I-Beam lends itself well to a trolly type system, this load capacity could easily be achieved with a wooden truss beam which would be considerably cheaper than an I-Beam. 10'span and 1000# load. No big thing.

To the OP:

You may want to check out Northern's fixed height gantry cranes. They use a 3" W x 5" H I Beam to achieve a 2000# rated capacity over 10'.

Picking the beam is quite easy - can even do that by just looking at other people's designs or picked off a chart without even calculating anything; it's the joints (welded vs bolted, brackets, etc) and stability (making sure when you got 1000lb hoisted up 10ft in the air that your whole hoist doesn't tip over) that are difficult. Wouldn't you agree? All I'm saying is error on the side of caution, you don't get to drop 1000lb on yourself, somebody else, or your dog more than 1 time.

In my opinion it's not the ability to do the calculations that makes a good engineer - anybody can plug and chug, it's the ability to foresee the issues (especially safety related issues) in the design phase, not in the 2nd iteration.

What kind of engineering do you to Sun?

[SundownIII]

Mot krig,

My undergrad degree is in Civil Engineering. Sat for my EIT (Engineer in training test) when I was in Officer Canidate School (Engineering, Ft. Belvoir) in 1968. Took and passed the PE Exam in 1973 when I was In the Engineer Advance Course.

Did my Graduate Work at Univ of Miami (Army funded) in Industrial Engineering with a concentration in Systems Analysis.

Most of the engineer consulting I have done over the last 30 years has been in the area of systems analysis/time motion work. Basically process flow. Worked in heavy fabrication as well as the textile industry.

As you mentioned, pickiing an I beam to carry the load (1000#) is a walk in the park. Most anything, within reason, would do. I'd be looking for the best deal on a drop if I was the OP. If you look at the Northern gantry crane I referenced, you'll see that it doesn't employ a "huge" I Beam. OP is not planning to be pulling the turbine engine out of an M1 tank.

To William:

Any retard can overdesign a project. An engineer designs a project to meet a specified requirement at the minimum cost possible. How much he "overdesigns" it, is a function of specified safety factors. The engineer also insures that "all the pieces work together". Makes no sense to overdesign an I-beam if the vertical supports/attachment won't carry the higher load. Just a waste of money.

The Professional Engineer community is actually "extremely" self enforcing. Bad engineers are quickly forced out of the system. We used to say that an engineer is judged in a court of law when he makes a mistake. Doctors bury theirs.

Engineers are held to a higher standard than most. A Professional Engineer (PE) applies his expertise in the professional field. Doctors and lawyers, on the other hand "practice" their respective fields. I guess that means that they never get it totally right.

[William McCormick Jr]

In this day in age you could not "over design" a building. No one would know how to build it.

And if cost is your concern China is the place to be. Bugs for breakfast, bugs for lunch, and bugs for diner. Heck you could buy the guys lunch for a buck, and do the community a service.

But seriously if cost, and time frame are your only concern, then you are no longer an architect, you are selling whatever good things you learned to appease someone that wants you to put your name on his crappy idea, so he can roll it over for a profit. Banks are not even investing in building, it is that bad.

One inch per foot is the minimum for commercial. And if you are building a hoist in your garage or barn or business. Everyone catches wind and next thing you know, there is someone there that wishes to use it. Or you get a job, or something comes up.

A friend pulls up and asks you to do a favor. He is with his wife that you dated but blew the load in your shorts out on the date with her. You still want to impress her. You do not know the weight of this object. Your friend has been telling her all night how big and strong your lift thingy is. The weight looks heavy but the guy says the guys at the airport say it weighs a ton. No one has a scale so you try it. It fits between the frame of your hoist.

I told the guy that I sell on an inch per foot "I" beam. Only lift one ton no more from the beam. You can lift cars from the corner gussets though.
You see it, and say you can lift five tons in the center with that over designed beam.

My guy is amazed when he lifts an airport snow plow tractor weight off his friends tractor, and they find out later it was filled with solid steel, and no one got hurt. It was closer to three tons. They thought it was sand filled.

You sell a guy a five inch beam and say

"it is "Rated" at 2,000 pounds, imagine what it will really take, I am privy to the inside calculations and over design specifications, the ones used on the Twin towers. It will lift two thousand pounds easily, jostling or under any normal condition".

They get the cheap chain hoist too. They go to lift this plow weight off, and the beam bends, the hook fails, and the chain hoist kills someone as it races up at fifty miles an hour. Hopefully it deflects off the beam and goes out through the roof and does not hurt anyone.

Now my guy even if he cheaps out with the chain hoist, he will just watch the hook break, the chain elongate. And realize it is heavier then they thought. Could any of this be real to you?

I was just working on a building, they are putting a huge stainless steel tank, and stone waterfall up on the roof. That is always a possibility in a commercial building. Is your building ready for that with the big five inch beam?

I am really not bashing you so much. I just find that all the calculations seem to go out the window when there is pressure from the money.

Sincerely,


William McCormick

[William McCormick Jr]

I was talking to the architect on this job, and he is from Chicago. That is why he probably got the job, because he does heavy quality work. In Chicago you learn what air pressure can do real quick as an architect.

I commended him on his steel choice. And I told him that in the area I don't normally see such heavy steel.

But I also stated for the record that if a tornado, of substantial proportion came along. And someone left a door or window open. Those doors could see the street.

Even that half inch wall 6"x6" box tubing could bend. Although even I believe it is unlikely that would happen. Only the rollers hold those Nanowalls in, so there could be a problem in a severe tornado.

Fortunately you do not see severe tornados in those parts much.

I was also a little concerned about the locks on the Nanowalls. And the way they stay when they are open. You cannot lock them open. So if someone was to stick their head out of the door. And a gust was to suck them shut you could get hurt. They close like a guillotine

But all and all not a bad job.

They open real nice and close real nice.

But that steel work is approaching very high quality. So accurate too. Really high quality steel work. Nice penetrating welds. Exactly square. And within 1/16" of an inch in measurements.

Anything less and it would have been a poor job.


Sincerely,


William McCormick

[triptester]

Here are a couple sites that list beam size for gantry cranes.

.http://www.vestilmfg.com/products/mh...gantry-fhs.htm

http://www.wallacecranes.com/triste1.htm

http://www.hoistsdirect.com/

[William McCormick Jr]

You can see in that link that triptester posted, that the legs and gussets, support the "I" beam out a foot. That is not as good as going all the way. But it does make a difference.

I still say that even those are light for a hoist that leaves it up to someone without a scale to tell what 2,000 pounds is.

What happens is that someone uses that gantry in a boat yard on gravel. And people see it pick up something very heavy maybe 4,000 pounds. You think that thing lifted it like nothing. But you put it on nice smooth cement. And out go the legs. When the legs go, the casters, turn and drop the weight. Or jostle it.

I used to build and design hoisting equipment. And special dollies for yachts in a rigging shop. And for high end race boats. I even built Scott Shafiroff his shop dollies for his race boat shop.

And I will tell you, it can never be enough. It will always be overused, and abused. If only by a new guy. I often would tell the buyer something was too light for what he wanted. But he took it anyway.

One thing people do not see coming, is the composite wheels. When the composite goes one day suddenly you can get catastrophe. It can brake the wheel. Or break the metal wheel if it comes down wrong. Tilt the load. Anything is possible. Having built them over twenty five years ago. I have seen over time that even the very expensive nylon coated wheels, coatings can age and crack with time. Fortunately it is just a covering to absorb small bumps. And you can usually survive the failure and then replace the wheels. It is an art to make something good that lasts.





Sincerely,


William McCormick

[SundownIII]

Wow.

I though we were talking about a beam to lift 1000# as described by the OP.

Now we're talking about designing the twin towers.

[William McCormick Jr]

It is funny but I took this to the edge. And believe it or not everything is totally related to everything else.

I was actually trying to get you to laugh a bit. And look at it from my point of view. I really do see it from the architects point of view. I hate to see them fudge to get jobs moving. I love when they are as hard as steel about beam sizing. It makes my job cake.

But I did not even touch on the things that these guys on the forum already know as common occurrences. One of them is lifting something off, or out of a land vehicle, trailer or boat.

Ask them how many times when they are lifting the 500 to 1,800 pound load out of, or off of something, does it hang up? A stuck bolt, paint, rust will do it. I have been amazed by rust the super welding substance of God a few times.

How many times does the vehicle drop, or come off the ground. I have seen it a few times myself personally. That is why although as you say the five inch beam might just be able to handle the 2,000 pound load. When you are handling the 2,000 pound load it is immediately a 4,000 pound load. By all the common events that go with handling it.

Not to mention the expert saying some unknown object weighs a ton. Ha-ha. That almost got me a few times.

I have myself lifted the van a bit, while taking something out of it. And I really practice a fair amount of awareness of what I am doing. I just missed it. I just did not see it from that angle.

I hope we can be friends and get architecture back to where it should be.

Someone wrote something, it was something like this. We have built great castles in the sky, now we should put foundations under them.

Sincerely,


William McCormick

[farmersamm]

Interesting note on beam sizing

I'm no expert, but I do have a gooseneck flatbed trailer rated at 24,000, and the clear span is about 18' between front tandem, and coupler. It all is held up by two 10" pieces of channel for the frame rails. (I'm pretty sure it's the right size, would have to measure them to be 100 percent)

And, I would assume, there's a good healthy safety factor because it's a very dynamic load, travelling over a road surface and all. Lot of G forces with road irregularities I would think.

[farmersamm]

I checked the measurements when I just went out and fed, they're 10" deep channel, medium weight.

[William McCormick Jr]

Some of those metals are not structural steel like you find in a building, and some of them are mechanically hardened or heat treated by forming or process. Some of them are reinforced by the bed material as well. Or other structures that bolt to the frame. Some of the axil mounts go way forward and way back. Cutting down on the span.

On truck or tractor frames there is no load right in the center of the chassis, it is spread out. Or put over the axles. On truck frames the chassis connects the front to the back of the vehicle. Rather then being a support for a single point load, like a beam on an "A" frame.

Some of the trailers especially the low to the ground, moving trailers. And heavy duty flat beds, flex as you load them. That would be bad in a building where the floors even Terrazzo floors would crack.
If you look at the beams on trailers they are often crowned up in the center. Before you load them. You can order "I" beams special with a crown.

If the trailer had 18" beams of standard structural steel it would hold rather solidly 72,000 pounds. Without much flex at all. That would be weight dispersed across the entire area of the 18 foot span.

Since it has 10" beams of unknown material, I will only say what I believe a standard structural beam found in a building, 10" high, would hold in that situation. I Would put the weight that it would seem to hold well or at least perform at 18,000 pounds. Stacked only in the 18 foot span, no cantilever load.

At about 18,000 pounds, it will flex. I would not recommend a 10" beam over 18 feet. Because it will flex. Not something good for loads in a moving truck.
You will be shifting loads, tightening them the whole trip.

If you put a narrow, 18,000 pound load like a hydraulic shear, across the truck in the center of the span held up by ten inch beams. And you hit a few good pot holes I would bet the trailer becomes unstable as the bed flexes violently.

Sincerely,


William McCormick

[forhire]

Trailers are a balance between strength, weight, and capacity. I imagine many have very little safety margin. The goal is to load the trailer with the most goods while keeping it light. If you over build the trailer then it affects your net load. Many trailers use heat treated rails and may be bowed to increase the capacity without increasing the weight.

My question... going back the original posters question is this...

How much deflection is considered acceptable in an overhead gantry? What is the standard within the industry? Knowing the acceptable deflection would help someone calculate a safe design with an appropriate safety margin based on the material chosen. I doubt you can simply look at the dimensions of any material and divine it's capacity. I'm certain that the acceptable deflection in construction, trailers, and lifting are very different. Anyone have the real numbers?

[farmersamm]

I don't do links

For a good discussion of a gantry crane build, complete with calculating methods......................

Do this search: submarineboat.com gantry and hoist"

It took about 2 minutes to find this They gotta new thing these days........search engines

[farmersamm]

I like Yahoo, but others prefer Googley Oogley

[William McCormick Jr]

Sam that is a clear case of stretching a material past its design limits. You are despicable.

Sincerely,


William McCormick

[William McCormick Jr]

I will be honest, zero humanly conceivable deflection is optimum. Any deflection is going to give you some spring.

I checked out that gantry link. And to me 1.75 inches of deflection, without jostling, without sticking, hanging up, or wench problems. Seems a bit high. I do not know what 10,000 psi moving 1.75 inches or much more during an accident, will do exactly to a lifting bar. Or a piece of the object you are lifting being ripped off. But I would imagine that you might be running for cover if it let loose.

I know an engineer and a business owner told me not to stand behind the engine hoist. Because someone got hurt when something broke. And the hoist the guy was standing behind hurt him bad.

I do not know if the hoist springing up, and hitting the hood of the car at that speed and deflecting was enough to send it into him. I was just told not to stand behind it.

I know sometimes if you look at engine hoists they are missing some bolts. All the rattling they get from being moved on hard concrete. Can leave them half assembled. Always check that before you use it.
Some designs might actually allow the boom to come back over too. So if you are making your own, make sure you stop the boom from doing a 180 degree swing.

Sincerely,


William McCormick

[forhire]

I will be honest, zero humanly conceivable deflection is optimum. Any deflection is going to give you some spring.

I checked out that gantry link. And to me 1.75 inches of deflection, without jostling, without sticking, hanging up, or wench problems. Seems a bit high.

I looked at this a few days ago myself. I too found 1.75" of deflection a bit high. This is why I asked the question. Does anyone know if this is an acceptable standard or did he simply decide it sounded ok? Sure near zero would be ideal but that too can lead to seriously over building.

I did find this while searching pertaining to jib cranes:
Capacity: The maximum live weight that the crane is designed to support. For jib cranes, the design load is based on the capacity, plus a hoist and trolley allowance (15% of capacity) and an impact al lowance (25% of capacity). The allowable deflection of the crane is calculated using the design load plus the hoist allowance. Load testing can be performed to 125% of rated load capacity. Standard Gorbel® jib cranes are available in capacities up to 5 tons (4536 kg).

Deflection: The difference in elevation at the tip of the boom between an unloaded crane and a fully loaded crane; usually measured in inches. Gorbel tends to have stricter deflection criteria than others in the industry. Typical deflection of Gorbel® designs (where L = span of the crane in inches): WC200, FS300, FS350, FS350S, MT400: L/150 WB100: L/450

So I went directly to Gorbel and their standard for a free standing bridge crane is:
Consider both deflection and stress. The difference in elevation of the track between an unloaded crane and fully loaded crane; measure in inches. L= support center distance. Gorbel tends to have stricter deflection guidelines than others in the industry because we consider both deflection and stress.

Work Station Cranes: Typical design guidelines are L/450 for bridge cranes

So at 10 feet the deflection of a jib crane should be less than 0.8 using 120/150 (120/450 is 0.26 using the higher standard) for example. But the bridge crane would be 0.13 using 60/450.

Of course it sounds like others in the industry use a lesser standard. What's acceptable?

[William McCormick Jr]

Farmer Sam, I just wanted you to know. That I saw this lovely young lady, after seeing the Camaro at the car show. And I just had to get you a picture. We were discussing the modifications to the headlights on this years Camaro.

No GT 40 at this years show. I saw it there a few years back. It was pretty wild. I just cannot believe they would not bring one.

This is for you Sam, Ha-ha. I figured I owed you for all the ones you posted.



Sincerely,


William McCormick

[farmersamm]

The purpose of the post was to give people links to the "calculators". How much deflection you're willing to accept is up to you.

I regurlarly use my 3pt jib crane to lift in the 12-1500lb range, and occasionally exceed 2000lbs. The deflection is pretty significant over a ton, you can sight the main mast and see the bow. Do I care? No

First off, I obviously haven't reached the yield point at 2000lbs.

Second, 2000lb loads aren't the norm for the crane. Usual working loads are around 1500 or less, with the bulk of the working loads in the 500-1000lb range. My peak load/max load cycles are infrequent. Load cycles are important. I would imagine that excessive deflection over many cycles would lead to fatigue failure at some point.

While a jib crane, designed like I designed mine, isn't a gantry crane, it serves to illustrate the beauty of the material. Metal has an amazing amount of tensile strength, and it has "memory" to a point.

If a person feels that 3/4 inch deflection is unacceptable, then beef it up. It's your money. In my strictly uneducated opinion, as long as you're not near the yield point, and you don't intend to place the crane in high cycle service, greater deflection is acceptable.

I read a Department of Labor standard for port cranes. It stated that deflection may not exceed 1/750 of the clear span, unless design specs allowed otherwise. So ya see, it all depends on who ya talk to. And even this strict spec has a caveat.

It's mostly a matter of common sense, and some familiarity with the material.

I have ramps for my trailer, built in two pieces with a "floating" center support. Clear span at any point is 8 feet. Wheel width ramps which are 16' overall length. They're built out of 5" channel. My largest tractor weighs around 10,000lbs. With the load distributed 70/30 rear axle front axle, the max load is 7000 at any given point on one pair of ramps. Split in two because there's two ramps, the load is then 3500lbs on the individual section. There is positively no deflection on these ramps (well maybe a tad). Just how heavy do you build?? (I built the ramps this long to decrease the slope when loading, tractors have a nasty habit of rolling over backwards when climbing steep slopes)

[farmersamm]

Mr. McCormick, a very nice picture

We only seem to have agricultural trade shows around here, and definitely no "tractor babes"

[William McCormick Jr]

1/750 of the clear span is probably about where you would like to be.

Sincerely,


William McCormick

[William McCormick Jr]

I was dying waiting for my friend to take that picture. I am hiding a big grin there.

Sincerely,


William McCormick

[hp246]

Not that it matters, as you guys are having too darn much fun with this thread, but I did manage to build a gantry style lift that was sufficient for my needs. Thanks for all the imput guys, I realized that I was over engineering the whole thing. I didn't even use an I-beam, just some rectangular tubing that I had laying around.

Any want. William McCormick and farmersamm, please proceed to posting more pictures. Thanks.