Crane I-Beam Cantilever

I-shaped. And big.

Even if the I beam will support the load are you sure the column can accept the bending moment ? How many people could find themselves under the collapsed building if this column fails ?

a agree. web stiffeners and steel plates bolted {but perferrably welded} on both sides of the web and extending well above and below the jib arm should prevent the column from buckling.

a steel plate welded to both flanges would also reduce horizonal deflection. if you're planning on building this without the help of an engineer, build it with what you think would strong enough to carry 5 times the maximin intended load. if your not sure of your skills, hire an engineer!

I'm going to go out on a beam here , and suggest that the OP has every intention of hiring the proper PE to certify any design he comes up with, but merely wants some ideas for a starting point. It's a lot less expensive to come up with a design, along with all the elevations, etc, and then have a Civil or Structural Engineer make the necessary adjustments before certifying it... as opposed to having the entire design done for you starting from scratch. At least I hope that's what the OP is planning to do.

aanderson8... if you provide much more detail and specifics, perhaps someone here could get you closer to a baseline design. But following the rest of the advice given here so far is absolutely crucial.

I also hope that this is what the OP intended to ask for, but it is not what they actually asked of us. As far as we know this column might be a decorative but massive Doric column of stacked marble blocks with superb vertical strength but with little lateral support. This is why the OP is asking for a counterweight suggestion.

"and suggest that the OP has every intention of hiring the proper PE to certify any design he comes up with, but merely wants some ideas for a starting point. It's a lot less expensive to come up with a design, along with all the elevations, etc, and then have a Civil or Structural Engineer make the necessary adjustments before certifying it... as opposed to having the entire design done for you starting from scratch. At least I hope that's what the OP is planning to do."

Silly remark. I would not accept such a job. To just check the calculations of somebody who, clearly, has not the background to know what problems might occur would require much back-and-forwarding of questions and answers, and might still risk my reputation and professional license if there was misunderstanding. It would cost less to just give me the job.

An experienced structural engineer is much better able to make good suggestions but he would need much more information on the existing conditions, does the beam really have to cantilever or can it have a diagonal brace under it? is lateral restraint available? etc. etc.

Silly is, as silly does.

It's not a silly suggestion at all. It happens all the time. I fact, I do it all the time. I'm not a PE, so I have a PE check my own designs and make adjustments on a regular basis, and then certify them as sound designs. This is nothing original or rare. Where have you been?

The cost difference of another engineer doing all the initial design work and drafting, compared to doing it one's self and getting it checked, is enormous. And when the result is equivalent in safety and efficiency... wasting that extra money would be a very poor management decision, indeed. I wouldn't trust my calculations, because Civil or Structural is not my specialty. But I can certainly get it close. And if it's not quite right, or if it's overkill, I'm made aware of it and it is fine tuned.

It's a good thing you would not accept the job, because I would not hire you anyway if you couldn't handle it. Others can. At less cost. And with enough skill and enough confidence in their abilities and communication, where they wouldn't worry about their reputations. So I guess that wouldn't be the gig for you, passingtongreen.

I think that you, OBE, are missing an important difference that PTG is probably trying to make here. You would be bringing to a PE a set of documents and calculations that show that you have a clear understanding of the fundamentals and the language that a PE needs to make a valid assessment. Any uncertainties or discrepancies the PE finds in your plans will then be communicated to somebody that both understands and respects the integrity of the PE. While this does not guarantee that you will get approval for any specific project from any particular PE, an iterative design process with you will make forward progress toward a clear understanding of what can and should be done to make a safe design.

This is not what our OP has done. Our OP has not shown any understanding of the engineering discipline, the vernacular to convey useful information to an engineer or the gravity of the situation that he wants completed. The OP has only shown a desire to cut costs. With this in mind, no PE should ever approve a design such a cost cutter delivers them. The PE will never be certain if the information given accurately reflects the situation or if any design changes are understood properly or ever properly implemented. Any PE that approves a design this way risks lives and their entire career.

I don't believe we are opposed here. Except perhaps that some of you are assuming the OP is a dumbass that's getting in over his head... and I'm assuming he may be a GM or an engineer or designer on a project that he is in the process of designing, but isn't a specialist in this particular situation, so he's asking for some advice on his preliminary design. That is just the sense I got from his question.

He only wrote three sentences, so for any of us to be sure of our assessment of him, or his competence as an engineer, or what the full story is... well, that's impossible. To me, my scenario seems likely. Only someone with some type of authority or responsible backing, would be asking such a question. Some guy with a shovel or a 2x4 isn't asking this. And if he was, he wouldn't be building it. The size of material he is talking about here tells me that whatever transpires, or is built, is going to go through the proper channels and procedure. You guys are acting like if you give him some advice, he is going to go off by himself, with a 5 ton crane all alone, and bring a building down because of what you told him. I hardly believe that is the case. This is just a forum, for advice. Be realistic folks. Let's not inflate our relevance.

And as far as PTG, I was merely explaining to him that there are engineers that take preliminary work from others, and check it, adjust it, and certify it. He was stating that the only sensible thing is to have another engineer do the whole thing. That's not the choice most building contractors or engineering firms would make.

The situation you describe is clearly not that of the OP. You would not have to ask the question, you have the background to find out yourself. Unless you have experience with crane beams though, you might something un-usable. The deflection limits on crane beams and the lateral bracing for that long a cantilever could be tough.

Be aware, in some states, the design and design documents are required to be performed under the supervision of a PE, those that do this, disallowed your method decades ago.

"The situation you describe is clearly not that of the OP."

That's a large assumption. The only thing that's clear, is that nothing about any of this is clear. I gave my interpretation of what the situation could be, based on my career experience. I could be wrong. I could be right. Unless we eventually get feedback from the OP, we jus' ain't gonna know.

You had better hire a qualified licensed Structural Engineer registered in your state to design this crane beam.

Not only does this beam have to designed, there is the need to properly design the connection to the column for induced bending moment, impact factor, and shear (and possibly torsional stresses), but there is a very strong possibility that the existing steel column will need to be highly reinforced to resist the axial loads and the imparted bending moment....or replaced, as it will act as a "beam-column", thereby significantly reducing it's load carrying capacity. Additionally, the column baseplate will need to be structurally reinforced. Then the existing concrete footing will need to be analyzed for punching shear, one-way shear, two-way shear and soil bearing capacity. All of this work and materials will not come cheap.

My initial question I thought of when I read the OP's posting was: "why a 19 foot cantilever, and why this limitation?" It is far better to support the crane rail beam and the crane trolley between 2 end columns that feature lateral supports tied structurally to the concrete floor slab if it exists.

To echo others concerns voiced herein, this is not something to play around with, and it's failure will possibly lead to a massive amount of property damage and possible injury, dismemberment and even death of persons operating it or in its vicinity. If it collapses you will most likely face trial, and as a result of conviction, face imprisonment for a number of years. You will also face civil proceedings for resulting damages, injures and deaths caused by the collapse of this crane if you do not hire a PE to design and analyze the structural elements. To ignore this advice, in my opinion, will result in repercussions far exceeding the benefits of doing this on the cheap. Seen it happen several times in my career, and in 3 cases I have testified as an Expert Witness (for forensic engineering) for the Prosecution in the criminal cases....also I ended up testifying in the civil court proceedings which followed. The defendants all ended up in prison for no less than 10-years.

Signed,

CaptMoosie, NYS LPE

Civil, Structural & Environmental Engineer

how much head room do you have above the arm?

if there is a fabricating shop in your area, i'ld talk to them first. they're specialists in this field, and from my experiance they will usually give you the specs for these type of designs. the information you're looking for is just a matter of opening a book.