Full Moment Connection
Full Moment Connection
(OP)
An I-beam requires a bolted full moment connection to an I-column. I told my friend it requires an end plate with bolts to the top and bottom flange, as well as angle cleats/bolts to the web.
Whereas my friend is insistent that it's fine to just cleat the beam off the column and fix with a couple of bolts, since the moment transfers through the bolts via push and pull of F=M/d where d=distance between the bolts.
How do I explain to him why he is wrong?
Whereas my friend is insistent that it's fine to just cleat the beam off the column and fix with a couple of bolts, since the moment transfers through the bolts via push and pull of F=M/d where d=distance between the bolts.
How do I explain to him why he is wrong?






RE: Full Moment Connection
Typically, in design practice a connection is only considered a moment connection if both flanges are attached. That's not to say that other connections don't have some moment strength/stiffness but instead that they are typically neglected. Even a simple shear tab has some fixity associated with it. In some seismic retrofits, this additional fixity is counted on to classify the connection as a "partially restrained connection"
RE: Full Moment Connection
It will, however, rotate a bit before it does this.
With an end plate setup, with bolts acting in tension, very very little rotation is allow in the joint.
It's all about rotations and displacements.
RE: Full Moment Connection
The bolted end plate moment connection is very well tested (see AISC Design guide 4 on the use of these moment connections for seismic applications and AISC 358 with authorizes its use for Special Moment Frames). I have not reviewed it personally, but there is supposed to be a lot of testing that goes into justifying moment connections for Special Moment Frames.
I have never used angle cleats to create a moment connection. Though it strikes me as being similar to some of the "partially restrained" moment connections described by AISC. If so, they don't exhibit very good moment-rotation behavior in general. Though it may be sufficient for low demand moment connections (like you use for non-seismic and non-hurricane regions), but the current testing does not allow them to be used for seismic applications here in the US.
RE: Full Moment Connection
RE: Full Moment Connection
RE: Full Moment Connection