Balancing Pre-load
Balancing Pre-load
(OP)
I am currently working on a connection for between a tubular steel member and an I-beam The design is major over kill for the current application which uses four B7 -5/8Dia. alloy threaded rods to clamp and only needs to be rated for ½ Ton, however I am hoping if I design it correctly it could be rated for 2Ton or more.
Since the connection is square the situation easly simplifies to a threaded rod. Its 5/8 Dia. B7 Alloy ASTM A193. (I attached a CAD of the bolt) The Pre-Load would be 85 kpsi, (ASIC table J3.2 -making the 250lbs load negligible
).
Since there are three nuts, If you pre load one nut and then tighten the other nut to preload, the preload condition of the first nut will change.
I am wondering if there is a practical way to pre-load both nuts correctly? (IE: how would a worker do this?)
Thank you for your help.
Since the connection is square the situation easly simplifies to a threaded rod. Its 5/8 Dia. B7 Alloy ASTM A193. (I attached a CAD of the bolt) The Pre-Load would be 85 kpsi, (ASIC table J3.2 -making the 250lbs load negligible
Since there are three nuts, If you pre load one nut and then tighten the other nut to preload, the preload condition of the first nut will change.
I am wondering if there is a practical way to pre-load both nuts correctly? (IE: how would a worker do this?)
Thank you for your help.





RE: Balancing Pre-load
Cheers
Greg Locock
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RE: Balancing Pre-load
I am not worried about it with 1000lb.
But Ideally I would like to use the same connection for 3ton.
Or would you still considered 3tons insignificant, compared to the approximately 85kpsi pre-load? ie: not worry about it to much.
RE: Balancing Pre-load
personnally, i think you're worrying too much (the distribution of preload between the 4 rods) about a small detail of the design.
RE: Balancing Pre-load
I assumed I was being over worried, but thought it would be best to get second opinion.
(there are no other engineers in my office)