The 1/32-inch requirement "is" limited to where "the pin is expected to
provide for relative movement between connected parts while under full load"
- but I don't think that this limitation relates to "rattling". My
interpretation is that it relates to movement or rotation of the pin while
fully loaded, which is likely to occur for a lifting lug. Also, I've read
that the purpose of the 1/32-inch limitation is to minimize stress increase
due to a "line load" under a curved surface. The greater the difference in
pin and hole diameters, the greater the concentrated stress and potential
for local yielding and deformation of the pin hole. And the purpose for the
maximum design edge distance around the hole is to prevent "dishing" of the
plate beyond the load point.
It's been a few years, but I've also used these provisions for design of
lifting lugs. It is not clear that these provisions apply to lifting lugs,
since AISC provisions are for "fixed" steel structures. I had been
criticized for requiring a 1/32-inch oversize hole for lifting lugs, but if
you oversize the hole, I would only do so if the lug design is
conservatively designed to reduce stresses. As I recall, the best way I
found to meet the various code limitations was to weld a circular washer
plate on each side of the lug plate to increase the area across the hole and
stiffen the lug plate at the hole.
> -----Original Message-----
> From: Padmanabhan Rajendran [mailto:rakamaka(--nospam--at)yahoo.com]
> Sent: Friday, February 09, 2001 2:29 PM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: Lift Lug
> That requirement is not applicable for my problem. I
> am designing lift lugs on a skid. The requirement you
> have mentioned is for cases where the two connected
> parts cannot be allowed to rattle.
> --- "Sherman, William" <ShermanWC(--nospam--at)cdm.com> wrote:
> > What about the requirement in the same section that
> > states "the diameter of
> > the pin hole shall not be more than 1/32-inch
> > greater than the diameter of
> > the pin"?