Lifting Beam (Below-The-Hook Lifting Device) 2

[JP20]

I've been tasked with designing a lifting beam. I am studying/going through ASME BTH-1-2017. Regarding pinned connections in chapter 3, there is (4) modes of failure. The first three modes are tensile strength, single plane fracture, and double plane shear strength... the formulas yield an answer in Kips. Is this the ALLOWABLE FORCE acceptable on each pinned connection/area? I assume so but I wanted to get someone else's opinion who may have been over this already. Just want to make sure.. any help would be much appreciated. For what it's worth, IMO, they poorly word some (a lot) of what's in this book.

ASME BTH-1-2017 & ASME B30.20-2018

J

 

[ldeem]

Outside code requirements I tend to error on the side of caution and bump up plate and weld thickness. In lighter designs I make the plate thickness fit the shackle opening regardless of calculated thickness (always much thinner than what will fit in the shackle). Secondly a quick starting point on pin pull out is single shear plane at 30% of yield.

I am not suggesting you skip detailed calcs but use those results as bare minimum's. I have seen riggers in the field do all sorts of things.

Don't forget to check sling clearances. In your sketch you show the top shackle at an angle. Make sure whatever shackle you use and pin location provide clearance for the sling. Also, unless this is an engineered lift with a lot of QC be sure to check 30 degree sling angle case.