huangyhg

determine load rating of a lifting beam
i have a lifting beam that is detailed in the attached sketch (5/8" thick flat steel plate, 4'-1" long, 4" high, with 1 lug plate in the center). i to determine what the load rating would be on this. any help with calculating this would be great.
try this
and this
i don't mean to be rude but do you have any ideas on how to start this?

what confuses me is that it is not laterally supported in any way. if i was rating a standard beam (monorail for example). i would first determine the estimated lift that i needed to pick and then verify if the current beam was adequate. in this case, it is 4000 lbs. i would add the dead load of the beam and hoists, add an impact load of 15%, and then base it on a load test of 125%, therefore a beam that needed to lift 4000 lbs would have to satisfy nearly 6,000 lbs or 6 kip. i would then determine the max compression (fb=12,000,000/(ld/af) and compare this to my allowable compression (fb=0.6x36 ksi = 21.6ksi). i would then check tension, calculate moment m=pl/4, solve for fb=m/s and verify it is less than allowable 21.6ksi. i would then check deflection =pl^3/48ei and make sure it is smaller than the allowable l/600. i would finally confirm lateral is within 20% of the total load.
sounds like you're answering your only question ...
the beam does look narrow, "tippy" ... from your sketch i take it that the load is reacted at a pair of the grooves ? i guess you could consider the beam has fallen over (so the load is applied across the weak axis of the beam ...
look in f11 of the 13th edition manual for yielding and ltb. it should be noted, however, that all aisc equations assume that both lateral and torsional bracing is present at the
how do you determine the tearout force of crane hook on the lifting eye?
the article by david ricker that bridgebuster referenced above addresses the lifting lug and any tearout forces. however, i am still trying to calculate the beam only being a piece 5/8" flat steel (without any flanges).
my two cents!
without doing any calculation, that beam does not look right. an i have seen a few lifting beams in my travels. having said that, the loads you talk about (4000lb) is punny.
the beam has very little stability, and since the grooves are on the top of the beam i would assume that the load is applied above the cog and hence de-stabilising. moving the application point of the load to the underside of the beam would help.
is the load secured to the lifting beam? the grooves seem to indicate that the load is just hanging from the beam, saddled in one of the grooves. in that case a sudden movement, unequal loads or beam defflection would make it fall. not a good thing.
i calculate the lifting plate can handle 470 pounds when using a36 steel.

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