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RE: AISC LRFD Bearing Strength at Bolt Holes

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Rick-

I agree that the connection capacity would be the sum of the individual
bolt strengths. I think that this approach can be justified for normal
length connections with the assumption that as the material ahead of the
edge bolt starts to yield the load will be redistributed to the other
bolts in the connection, until they all yield or tear.

Check out Tables 7-12 and 7-13. Bearing values per inch material
thickness are given for both 1-1/4" edge and 3" spacing.

HTH,
Heath


> -----Original Message-----
> From: Rick Burch [mailto:rburch(--nospam--at)conterra.com]
> Sent: Tuesday, February 04, 2003 5:43 PM
> To: seaint list server
> Subject: AISC LRFD Bearing Strength at Bolt Holes
> 
> In the AISC LRFD 3rd Edition, Section J3.10 (p. 16.1-66), Eq. J3-2a
> gives the value for the design bearing strength at a single bolt hole.
> The equation includes Lc, which is the "clear distance, in the
direction
> of the force, between the edge of the hole and the edge of the
adjacent
> hole or edge of the material."
> 
> Picture a typical tension member, say double angles with a series of
> bolts in a single line, with 3" spacing between bolts, and 1-1/4"
> between the last bolt and the end of the angle.  This equation gives a
> smaller value (since Lc is smaller) for the end bolt than for all the
> other bolts.
> 
> My question is: In the connection for this member, is this correct
that
> one bolt has a smaller value, and the value for the connection would
be
> the sum of the values for the individual bolts? It seems a little
> strange that this one bolt would know to bear less than the other
bolts.
> This case was not in the 2nd Edition, since bolts with 1.5d edge
> distance or 3d spacing were treated the same.
> 
> Thanks,
> Rick Burch
> Columbia, SC
> 
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