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  1. #11

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    All this math.. I wasnt very good at it. The only math I can come up with is... BUY A CHERRY PICKER.

    Thanks for all your help. All in all... You guys prevented me from making a big mistake.. I have a beam all lined up and it probably wasnt going to work.. Plus I have to get the trolley and hoist yet too.. Adding it all up...

    A cherry picker would suit me better.

    More projects to come... thanks for your help..

  2. #12
    Join Date
    Sep 2005
    Location
    16919 Pole Rd. Brethren, MI 49619
    Posts
    4,383

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    I agree, if I could get by with a cherry picker I would, so much cheaper and so portable. There was one in a thread from Northern, real good. I have built several for garages, this one for my Bud. The wall stabilizes, load on the post and the other post has wheels in an arc.
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  3. #13
    Join Date
    Sep 2007
    Location
    Medford MA
    Posts
    542

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    Quote Originally Posted by shortgoroper View Post
    The beam will be set on the exterior wall (cinder block). then across to a perpendicular wooden beam.
    how big/strong is that wooden beam?
    how long is it?
    what kind of wood?
    what is it supported by?
    any joints in the wood?
    how are you joining the steel to the wood?
    where in the wood beam's span does the steel beam join?
    ...

    you have a more complex design than your first post implied.

    the load on the steel beam is being supported by the cinder block
    wall and the wood beam. worst case, all of the load is at one end
    or the other, which means that either the wood beam or the cinder
    block wall has to support the full load. plus, of course, half the weight
    of the steel beam, plus the full weight of the lifting gear.
    so now you have to also model the wood beam in the same manner
    as you have to model the steel beam

    plus the load is dynamic (lifting up/down, traveling side to side,
    and swaying), that adds a complication to the work.

    plus there is going to be a thrust (sideways force) on the wood
    beam -- imagine lifting an x00 pound engine and then sliding
    the trolley all they way in the direction of the wood beam
    and letting it crash into the wood beam (or the stops on the steel
    beam -- which will still transfer the force to the wood beam).
    that's a side-force on the wood beam, which probably can't handle
    it...


    frank

  4. #14
    Join Date
    Feb 2008
    Posts
    866

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    Excerpt from ASCE7, Minimum Design Loads for Buildings and Other Structures

    4.10 CRANE LOADS
    The crane live load shall be the rated capacity of the crane. Design loads for the runway beams, including connections and support brackets, of moving bridge cranes and monorail cranes shall include the maximum wheel loads of the crane and the vertical impact, lateral, and longitudinal forces induced by the moving crane.

    4.10.1 Maximum Wheel Load.
    The maximum wheel loads shall be the wheel loads produced by the weight of the bridge, as applicable, plus the sum of the rated capacity and the weight of the trolley with the trolley positioned on its runway at the location where the resulting load effect is maximum.

    4.10.2 Vertical Impact Force.
    The maximum wheel loads of the crane shall be increased by the percentages shown in the following text to determine the induced vertical impact or vibration force:

    Monorail cranes (powered) - 25
    Cab-operated or remotely operated bridge cranes (powered) - 25

    Pendant-operated bridge cranes (powered) - 10

    Bridge cranes or monorail cranes with hand-geared bridge, trolley, and hoist - 0

    4.10.3 Lateral Force.
    The lateral force on crane runway beams with electrically powered trolleys shall be calculated as 20 percent of the sum of the rated capacity of the crane and the weight of the hoist and trolley. The lateral force shall be assumed to act horizontally at the traction surface of a runway beam, in either direction perpendicular to the beam, and shall be distributed with due regard to the lateral stiffness of the runway beam and supporting structure.

    4.10.4 Longitudinal Force.

    The longitudinal force on crane runway beams, except for bridge cranes with hand-geared bridges, shall be calculated as 10 percent of the maximum wheel loads of the crane. The longitudinal force shall be assumed to act horizontally at the traction surface of a runway beam in either direction
    parallel to the beam.
    So what you're interested in building is a monorail crane. Assuming a hand operated crane with free-wheeling trolley, you don't have to increase the design load of the beam and you don't have to figure any lateral or longitudinal loads. Use an electric trolley or electric hoist and that changes.

    As previously stated, there are a few "cases" you are interested in.

    Worst case for block wall: when the trolley is closest to the block wall, essentially all the load is carried as shear on that end of the rail beam, and as a concentrated point load on the block wall.

    Worst case for the wood beam: when the trolley is closest to the wood beam, essentially all the load is carried as shear on that end of the rail beam and imparts a concentrated point load on the wood beam (and I would put money on the fact that it is undersized).

    Worst case for the beam: when the trolley is at the center of the rail beam, the maximum bending moment is developed in the rail beam, and one half of the total load is carried by each end of the beam.

    Using LRFD, assume 200 lb of gear in the trolley and hoist. 1.2 dead load + 1.6 live load = 240+3200=3440 lb design load.

    So think about a beam to wall connection designed to take this load, plus 1.2 times half the beam's dead weight (maybe 100 lb). Think of the same load and connection at the wood beam, which would likely need a column under it unless it is a very large timber.

    As for the beam, 3440 lb point load at the middle produces PL/4 ft lb of bending moment, and with 12' clear span, this is 10,320 ft lb.

    But when selecting a beam, you must realize that clear spans have reduced capacity due to lateral torsional buckling. So one must consult Table 3-10 of the AISC steel manual.

    To calculate deflection, you use the actual service live load, which would be 2000 lb, and use the formula PL^3/(48 EI) where E is the modulus of elasticity of steel (29,000,000 psi) and I is anything larger that the value that produces a deflection of L/360 (0.4 inches).

    Solving for I when delta = .4" is I=(2000*144^3)/(48*29,000,000*.4)=10.72 in^4

    Thus, you need a beam with a section moment of inertia greater than 10.72.

    W8x13 would be an excellent choice with phiMn@12' span =18,000 ftlb and I=39.6 in^4. Smaller sections might work, but that's the smallest section graphed on Table 3-10 and calculating phiMn@12' span for smaller beams would take a minute.

    That's the easy part. Now it you want to see something complicated, try detailing the connections. And then you'd have to go through the same procedure to see how overloaded that wood beam would be.

    80% of failures are from 20% of causes
    Never compromise your principles today in the name of furthering them in the future.
    "All I ever wanted was an honest week's pay for an honest day's work." -Sgt. Bilko
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  5. #15
    Join Date
    Jul 2006
    Posts
    1,508

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    Quote Originally Posted by shortgoroper View Post
    My question to you is... What size beam do I need for a clear span of 12 feet?
    http://www.tseq.com/products/mhequip/gantry-fhs.htm
    Caution!
    These are "my" views based only on “my” experiences in “my” little bitty world.

  6. #16
    Join Date
    Dec 2007
    Location
    National City CA
    Posts
    1,086

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    The thing is the LSS will tell you what the beam will carrie but they will not tell you what the supporting structure can hold. And that is the key.
    A cherry picker is cheap and easy. Yes they are slow but how often due you really plan on puling and engine?
    Boddy bagger gave all the proper calcs but to be safe you need to go 5 times the rated live load to meet code. I know your system is at home in a garage but still it should meet code just to keep yourself alive
    Miller Syncrowave 200 W/Radiator 1A & water cooled torch
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  7. #17
    Join Date
    Dec 2007
    Location
    National City CA
    Posts
    1,086

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    And you never gave us a weight you intend to lift although you did give us a description of what you intend to do.
    So for a 1 ton 12' long mono rail supported at the ends
    A W14X43 would work and give you enough extra to be safe.
    43 Lbs per foot = expensive stuff
    Miller Syncrowave 200 W/Radiator 1A & water cooled torch
    Millermatic 252 on the wish list
    Bridgeport Mill W/ 2 axis CNC control
    South bend lathe 10LX40
    K.O. Lee surface grinder 6X18
    Over 20 years as a Machinist Toolmaker
    A TWO CAR garage full of tools and a fridge full of beer
    Auto shades are for rookies
    www.KLStottlemyer.com

  8. #18
    Join Date
    Jul 2006
    Posts
    1,508

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    Quote Originally Posted by kcstott View Post
    A W14X43 would work and give you enough extra to be safe.
    At 35,000 pounds that should be plenty of safety factor!
    Trolleys for wide flange beams are hard to find, once you find one, and get back up off the floor you may need to float a loan to pay for it.
    Caution!
    These are "my" views based only on “my” experiences in “my” little bitty world.

  9. #19

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    Well... You guys point out some things I am not even thinking about. I ultimately wanted this beam in for pulling an engine on a Jeep. But instead of having the cherry picker tieing up a corner of my garage.. The trolley was going to be used so that I can just slide the chain hoist out of the way.

    I was going to place the beam in the center of my garage bay so that when I have a heavier item (200-300 lb) I could raise it off the floor and roll my 1000# rated welding table under it.

    I guess all in all the heaviest item would be that Jeep I-6 cylinder. I was also thinking of using it to maybe support the Jeep tub while I roll the frame out from under it.

    I like the gantry crane idea as well as the cherry picker.. I guess I will have to weigh out the price/space available/ease of use.

    Should I go with the gantry crane, I will build legs to support it and forego the use of the block wall.

  10. #20
    Join Date
    Jul 2006
    Posts
    1,508

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    Quote Originally Posted by shortgoroper View Post
    Should I go with the gantry crane, I will build legs to support it and forego the use of the block wall.
    These are decisions only you can make.
    Pipe is cheaper than square tube, for your loads you can get away with 4 inch schedule 80 pipe for the legs. With 3/4” x 12” x 12“ PL for the bearing plates, (w/ 3 1/2” thick slab).
    I would look at tying / securing your monarail / S-shape / wide flange beam into the block wall and the wooden beam.
    Two objectives when building shop cranes: 1, build a box if you can. 2, support the crane wherever you can so it cannot move.
    Caution!
    These are "my" views based only on “my” experiences in “my” little bitty world.

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