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Cantilevered Cloumn Systems

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To All,

Table 12.2-1, Sec. "G", of the ASCE lists the R values for cantilevered column steel moment frames, but my interpretation of a "cant. Col. System" is not a moment frame, but "fixed-free" columns with the moment taken at the foundation level, i.e. a "pole" type structure or steel columns embedded in a concrete grade beam. So, my question is, since these systems are "pinned" or "free" at the top of the columns, what would differentiate between using an R of 2.5 for item 1), (Special steel moment frames" and using an R of 1.25 for item 3), ("Ordinary steel moment frames"), since in either case there wouldn't be a moment connection at the top of the columns to design for either item 1) or 2)? The seismic force is obviously substantially different between an R of 2.5 and 1.25, so why can't an R of 2.5 be taken for any cantilevered one story steel column system?

Thanks in advance,

Larry Hauer S.E.

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