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Thread: what size steel I beam do i need?

  1. #1
    Associate Engineer
    Join Date
    Jul 2011
    Posts
    2

    what size steel I beam do i need?

    i'm building a shop at my house made of concrete block. before i put the roof on, i would like to install a hoist system to lift things like car engines, metal lathes, etc... my shop is 20' x 30'. i would like to place 2 "I" beams on top of the block from one 30' wall to the other, thus spanning a distance of 20'. these 2 "I" beams would each be placed 5' out from the center line of the 30' walls. in other words, the 2 "I" beams would be 10' apart. one beam 10' from the front of the building, and one beam 10' from the back. i'm planning on using trollies to hang another beam perpendicular and below these 2 main beams from which to hang a hoist on another trolly. i need this system to safely lift 1200 to 1500 lbs with minimal deflection. i probably won't ever lift over 600 lbs, but i want to make sure it's strong enough for any situation that i may create for myself. i understand that deflection is inevitable, but i would like there to be a little as possible. so, my main question is, what is the smallest beam i can use for the 2 main beams? i was thinking that a S8 x 18.4 or a S8 x 23 would be sufficent, but i need a second opinion from someone that is a math wizard. thanks in advance.

  2. #2
    Technical Fellow
    Join Date
    Feb 2011
    Posts
    1,045
    Hi Corpsman,

    Welcome to our little world here. The first thing is it is unlikely you will get a great deal of assistance with this as we as a group tend to not like offering advice in things where people can stand under and be crushed or killed if it fails. Your insurance company would instantly abandon you if someone go hurt. Therefore our standard answer is, "get a qualified Engineer to design it for you."

    Having said that, the risk is in your court and you have been warned, but there are beam calculators on this website that would provide figures that might be acceptable. A standard SWL (Safe Working Load) is generally accepted as 2.5-times the maximum working load. BUT, you do not yet know the actual load.

    Posit, you are removing a truck engine and forgot to undo one bolt on the mounts. The lift begins and in a very short time, the truck is being requested to leave the ground along with the engine. Suddenly the 600-lb is not looking so good.

    The bare beams should not rest on the wall, they should have footing plates to spread the load. The vertical edge of a concrete block will not carry a lot of compressive point-load. The beam needs to be secure from tipping to the side. A 5-degree twist in the beam can reduce its working load by as much as 40-percent. Suddenly that 600-lb now looks like 840-lb and well beyond the SWL you have envisaged.

    So, at your risk you take advice from me. Personally, I would be walking the yellow pages for local Engineers. Too many things you are not aware of and thus not considering.

    Finally, as an Engineer willing to take those risks with my own design for my own workshop, I have found over the years that a sturdy cherry-picker hoist far surpasses a fixed beam design. I have a 2-ton folding hoist and it has lifted everything from car and truck engines to a 3000lb lathe.

  3. #3
    Associate Engineer
    Join Date
    Jul 2011
    Posts
    2
    i didn't think that i would get an answer to my question, but i thought i would give it a shot anyway. although not a qualified engineer, i am a fairly logical individual, and have already considered all of the scenerios/possibilities you have mentioned. of course, there could certainly be aspects critical to this project that am yet to be made aware of. i understand that there is no way for you to know how much emphasis i place on my own safety, or the safety of those around me. that being said, i do all i can to ensure anything such as this i do, is done in a safe manner. after all, that is the whole reason i posted my thread on this forum. while i would love to pick up the phone and consult and engineer, the financial side of that is not so welcoming. i tend to over-engineer things as a matter of habit, and i feel confident that i can do this safely. as far as using a cherry-picker... there are many things that a bridge crane can be used for, that a cherry-picker cannot do. so, i understand your position, and at the very least, thanks for your concern.

  4. #4
    Project Engineer
    Join Date
    Feb 2011
    Location
    Spokane, WA
    Posts
    105
    Corpsman:

    How did you arrive at your S8x18.4 / S8x23 size?

    dale
    Last edited by dalecyr; 08-03-2011 at 05:33 PM.

  5. #5
    Associate Engineer
    Join Date
    Apr 2012
    Posts
    1
    I hope someone is still out there. I had better put out a disclaimer here first: "Follow my advice/plan, at your own risk." Now that that is over, let's talk shop hoists. I am just starting to build/design mine. Harrington is nice enough to include a load/steel beam table that is greatly helping me: http://www.harringtonhoists.com/tech...67%20rev01.pdf. I am looking at creating a hoist system in my home shop. Shop size is: 22'wx39'Lx16'H. I plan on running 30' rails with a bridge that spans 20'. Actual span will be closer to 18'. I have 4"s+ of concrete that is 4400PSI. I am planning on anchoring 6 - 13'x3.5x3.5x.250 tube steel w/8"x10" plates fastened with Redheads, to the floor. I will tie posts to the wall w/welded brackets at about 10' up, w/lag bolts. My rails will be S8x18.4 spanning 30' with a center post at 15'. I am building my own trucks, thanks again to the engineers at Harrington:http://www.harringtonhoists.com/prod...bID=16&priID=5. This will be designed for 2 tons. I plan on never going over 1 ton. My bridge beam would have to be S12x31.8x20’, if single for 2 tons. To maximize space upward, I am thinking about placing two S8x18.4x20’ beams for upward height and stability instead. I might be able to build my hoist bracket between the two, thus raising the hook/hoist higher and out of the way? I wonder what people will think of that? Please feel free to critique.

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