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Drivable Man-Lift on Sprung Floor Under 2000lbs?

Discussion in 'General Advice' started by JHAYTER, Feb 26, 2016.

  1. JHAYTER

    JHAYTER Member

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    Location:
    Kingston, Ontario
    Hi Everyone,

    We have run into a weight issue trying to purchase a new man-lift to be used on our sprung stage at The Grand Theatre in Kingston, Ontario. We are currently using a push-around vertical mast lift which weights around 905 lbs without an operator (19' platform height), the lift we would like to purchase is a drivable scissor lift weighting over twice that weight, 2,400 lbs without operator (19' platform height). The push-around vertical mast lift is slow and can make a LX focus take forever (having to raise and lower the operator with every move), and a drivable at full height lift would pay for itself in labour savings in a couple of years easily.

    We have had engineers inspect the stage (rubber pads, 2x4's on 16 inch centres, with 2 layers of 3/4" ply, and a top layer of meso) and denied the use of it with concerns that the 3/4" in ply would be over-stressed.

    The engineer mentioned we would need to find a machine about 15% lighter to be able to use it safely, however I can't seem to find a drivable lift (either vertical mast, or scissor) in that weight range that can also reach the 19'-25' platform height. I know another theatre in ontario that has the exact lift we would like, and uses it on their sprung floor (not sure of the construction differences).

    If anyone knows any products out there that might meet our requirements or if you have some advice, Please let me know!!

    Thanks!
    Jon
     
  2. sk8rsdad

    sk8rsdad Well-Known Member Premium Member Fight Leukemia

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    Location:
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    I may be that theatre.

    We use a Genie GR-20 Runabout on our sprung floor stage. Our floor construction is different, using something resembling rubber pucks on concrete slab as the subfloor on something closer to 6" OC. Scissor lifts may be a better option for you; they weigh more (the GS-1930 is 2700lb) but the point load can be a fraction of a mast lift because of the larger footprint. It wasn't a good option for us because storage space is at a premium but there are a lot of really good reasons to prefer a scissor lift.

    How do the engineers feel about adding another layer to your floor?
     
  3. Footer

    Footer Senior Team Senior Team Premium Member

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    Location:
    Saratoga Springs, NY
    What is the PLF of your stage that the engineer gave you? Does you stage creak when running a grand piano around on it? A grand piano drops 400# per wheel on the deck. That is nearly what a scissor lift does. The Blow through rating on doubled up ply with maso is extremely high, especially on 16" centers.
     
  4. JHAYTER

    JHAYTER Member

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    Location:
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    Our floor has the rubber pucks as well on concrete slab, should have mentioned that instead of calling it "rubber pad"....The lift we were looking at buying is a scissor (Skyjack 3219). i was thinking the same thing about the point load with the footprint, unfortunately, still denied. He did mention adding another layer to the floor, however,downtime is at a premium for any kind mid sized project, but we haven't ruled this idea out. Just hoping we might find another solution without going this route. He also mentioned having loose sheets of ply to move around where we needed to drive, but at that point we aren't saving much time or labour.

    Good ideas though! Thank you
     
  5. JHAYTER

    JHAYTER Member

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    Location:
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    The stage doesn't creak or sound in distress when we roll our Steinway D 9' (990 lbs) over it whatsoever.... He listed 320 lbs psf as the concentrated load for the stage and 470 lbs concentrated per wheel of the lift
     
  6. SteveB

    SteveB Well-Known Member

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    Location:
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    We use a JLG MVL unit with platform at +19-6 and working height of about 25ft. It's about 2300 lbs.

    Our stage is very similar in size to yours except we re-enforced the floor when we replaced it so it's on rubber pads, then runners, then 2 layers of 3/4 ply, then 3/4 oak T&G. The floor does not creak from JLG weight. We fought with the architect to get the add'' 3/4 ply installed as we had been using the JLG for a few years and had the same attitude as you, it saves hours of labor.

    And I would suggest a single person lift over a scissors as the smaller footprint lets you get it into a lot of tighter spaces. Our JLG has the extended bucket which has been extraordinarily useful on a lot of occasions, so is recommended.

    Now you only need to find something that won't kill your floor.
     
    JHAYTER likes this.
  7. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Occupation:
    Theatre Consultant
    Location:
    Oak Park, IL (708)983-5792
    Thank you for confirming 2 layers of 3/4 on sleepers 16" on center is inadequate for a stage floor. When Im forced to use 3/4, I go to sleepers on 12" centers. Usually 1 1/8" will span 16" (or really 12 1/2").
     

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