Thickness of Lifting Lug
Thickness of Lifting Lug
(OP)
Hi All :
As described in "Design and Construction of Lifting Beams" by David T. Ricker the minimum lug thickness should be 0.5in, in order to prevent dishing.
However for my project :
1) Weight of the equipment to be lifted is only 3000 lbs.
2) 4 lifting lugs will be used.
3) I can only go upto 3/8in lug thickness. What should I do ?
What formula did David T. Ricker used to reach to the conclusion of 0.5in ?
Thanks,
Kapil
Structural Engg.,EWI
As described in "Design and Construction of Lifting Beams" by David T. Ricker the minimum lug thickness should be 0.5in, in order to prevent dishing.
However for my project :
1) Weight of the equipment to be lifted is only 3000 lbs.
2) 4 lifting lugs will be used.
3) I can only go upto 3/8in lug thickness. What should I do ?
What formula did David T. Ricker used to reach to the conclusion of 0.5in ?
Thanks,
Kapil
Structural Engg.,EWI






RE: Thickness of Lifting Lug
RE: Thickness of Lifting Lug
RE: Thickness of Lifting Lug
RE: Thickness of Lifting Lug
RE: Thickness of Lifting Lug
AISC's provisions for lugs were originally developed in ASCE Transaction Paper No. 2023 by Bruce G. Johnston, "Pin-Connected Plate Links"published in 1938. This paper presented some sophisticated formulas to prevent failure, but these formulas never made it into the code.
The approach published in the AISC specifications until the 9th edition included a cryptic provision for dishing. The approach was in Article D3 of the 9th Edition, and was to size a lug for fracture at the side of the pin hole at 0.45 Fy, and then provide a higher factor of safety for the other potential failure modes: bearing, failure beyond the pin hole, and dishing of the entire plate.
The geometrical requirements of part 2 of D3 prevented the other failure modes, but didn't explain things clearly.
The requirement that "the edge of the member or element shall not exceed 4 times the thickness at the pin hole" was meant to prevent dishing of thin lugs. It might have been clearer if it had been stated the other way: e.g., the thickness of the plate shall not be less than 1/4 the distance from the edge of the pin hole to the edge of the member.
This requirement can result in some pretty thin lugs, but was not meant specifically for construction conditions. Curiously, the dishing criteria seems to have been left out of later editions of the AISC manual.
RE: Thickness of Lifting Lug
RE: Thickness of Lifting Lug