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Re: double bolt rows

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Multiple rows of bolts do increase the rigidity of the connection.  A rational and conservative design method would be to design the bolt group for the full eccentricity between the centroid of bolts and the support.  That way you wouldn't have to consider whether the support or the bolt group is more rigid and you can use the same connection design for either case.  In most cases, it shouldn't make a big difference in your design anyway because the drag forces multiplied by Omega are likely to influence the design more than the increase in eccentricity for the gravity loads.

Jason Emoto

>>> Mark Pemberton <Markp(--nospam--at)> 04/24/01 03:29PM >>>
We have found in our office that many times a double (or triple)
bolt row is required at steel beam connections that are part of
the collector system as these must be checked at omega level
forces.  This would seem to produce a degree of rotational rigidity.
Does anyone know of an approach to use for determining the
moment induced by this rotational rigidity?
We have found an approach to addressing the rigidity issue for
a single bolt row in an old "Steel Tips" manual, but cannot seem
to find the issue addressed for multiple bolt rows.
Is this something that is typically ignored?  Or, perhaps avoided
by using a single bolt row at all cost?

Mark Pemberton, P.E..

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