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RE: Special Moment Resisting Steel Frames (SMRF)

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Title: RE: Special Moment Resisting Steel Frames (SMRF)

You're quoting an R factor (4.5) that doesn't match up to the established categories in the 1997 AISC Seismic Provisions. Therein, Special Moment Frames (SMF) have R = 8, Intermediate Moment Frames (IMF) have R = 6 and Ordinary Moment Frames (OMF) have R = 4. Each of these systems has a resulting force demand that is intended to correspond to the level of ductility that can be derived from the member proportions and connection detailing required for the system.

Moment-frame connection testing is required in all cases, unless you take R = 3 or less and just design the frame according to the basic AISC Specification for Structural Steel Buildings. However, you can often rely upon existing tests to justify the connection design you're considering, thereby avoiding the expense of project-specific testing. For the reduced beam section (dogbone), there is a lot of testing that has been completed to date. You can find it in SAC documents.

Charlie


-----Original Message-----
From: Elly rejuso [mailto:Erejuso(--nospam--at)rmbyrd.com]
Sent: Wednesday, February 16, 2000 8:12 PM
To: seaint(--nospam--at)seaint.org
Subject: Special Moment Resisting Steel Frames (SMRF)


If a SMRF is analyzed using an R=4.5 and the connections designed are "Dog Bone" type, is there a mock- up test required for the beam-to-column connections?





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