Subject: Blue Book Revision - Strong Column / Weak Beam Req'dmt
From: Eddie Gonzalez <Eagonzal(--nospam--at)ENG.CI.LA.CA.US>
Date: Tue, 04 May 1999 08:06:21 -0700
While on the topic of code updates, the seismology committee is updating the
Blue Book (actually it is more turquois now). One item that I am aware of is
revising Section 1918.104.22.168 of UBC such that the "Strong Column / Weak Beam"
check is based on a "story/level" approach in lieu of a joint approach. That
is "SMc = Sum of the nominal moments strength of all columns framing into the
UNDERSIDE OF A LEVEL for all columns acting to resist lateral forces in the
direction under consideration. SMg = Sum of the nominal moment strength at
each end of each girder, for all girders OF THE LEVEL acting to resist lateral
forces in the direction under consideration." (capitals added by me for
The commentary is to explain that this modification is intended ,"to consider
the sum of column and girder strengths over an entire story rather than at each
>From my understanding, several folks have advocated for such an approach since
1991, including Priestly and Uang.
Seeing that this measure will eventually make it into our codes, perhaps some
of us can begin to comment on this proposal.