huangyhg

weak column/strong beam
as a continuation of an archived thread (
as the originator of that thread, i feel your pain. i can't recall all of the research that we did for that project, but we ultimately ended up using dog bone moment connections. i seem to remember that it was very difficult to make my siuation work using the other types of moment connections. i also seem to re
i did receive a response from aisc. here it is:
"the idea behind the moment frames found in the aisc seismic provisions (i.e. smf, imf and omf) is to establish a design where we achieve strong columns/weak beams. otherwise, a localized failure in a column can result in a global collapse scenario for floors above the localized failure. hence all smf and imf prequalified moment connections are based on strong column/weak beam testing.
please note that omf does not require the use of prequalified moment connections. that is, any moment connection, even those for static loads (i.e. those found in the aisc manual) may be used.
hence one can conceivably design a single-story omf with weak columns/strong beams and avoid the multi-story collapse scenario.
in such a case, the plastic hinges would form at the tops of the columns rather than in the beams. one would need to consider the column anchorage rigidity when attempting to determine when a plastic hinge will form at the top of the column, as the number of hinges in the frame will defined when the frame mechanism will develop and hence when collapse will occur. that is, one cannot treat the column anchorage as a hinge (pinned connection) or as a fixed (moment connection) unless it has been designed that way, which is critically important, as it affects the load which will develop a plastic hinge in the column top (i.e. column anchorage affects the moment diagram of the column.)
however, omf have requirements for continuity plates within the column, as again, the seismic provisions address moment frames from a strong column/weak beam perspective. having said that, you would need a building official to approve the design you mentioned as an omf."
my problem is i cannot use omf because of the seismic design category. yet my member sizes are controlled by wind drift. in aisc 341, the column-beam moment ratio does not apply to imfs, only smfs (sections 9.6 & 10.6). this seems to be the step that would ensure strong column/weak beam - is this correct?. if this step is not required for imfs, does that mean the strong column/weak beam requirement does not apply. in using the design procedure in aisc 358 for rbs connections, i don't find a step that checks the column capacity. i don't want to have to use w10x100 columns for a one-story building. any thoughts or comments on aisc's reply.

__________________
借用达朗贝尔的名言：前进吧，你会得到信心!
[url="http://www.dimcax.com"]几何尺寸与公差标准[/url]