Moment-connecting a coped beam

[UcfSE]

I need to provide a moment connection for a beam that is coped on the bottom flange. The coped area is 4" x 1.625" according to the shop drawings, plus the gap between the end of the beam and the column. The top flange is square and about 0.5" - 1" from the column flange it frames into. This is a W24x76 beam, each side, framing into a W14x61 column connecting to the strong axis of the column, beam bending about its strong axis. This is new construction in which the shear-only connection is being changed to a moment connection after the beam is erected, before the building is complete.

The beams work simply-supported as well as moment connected. The idea is to reduce deflection of the beams.

I'm thinking to provide a 50 ksi plate, matching as close as reasonable the flange size of the W24, to fill in the gap at the bottom flange and have the steel guys prep the flanges for a full-pen weld top and bottom. I will check the plate buckling and provide a stiffener if needed. Does this sound reasonable? Is there anything I should be watching out for? Fatigue is not an issue here, and welding is preferred since it will be hard for them to punch holes in those big beams in the field.

 

[aggman]

Your approach seems reasonable to me. The only thing I could comment on is that the welder probably will not have enough access to weld all the way across the flange without stopping mid way (9" wide flange). That would concern me on the full strength of the weld. You may also consider lapping the bottom flange plate and allowing the plate to be slightly wider than the flange. Say something like a 10" wide plate. This will give better access but may require welding accross the end (overhead) to keep the plate length reasonable. I guess a lot depends on the actual design moment.