SCBF question

[broncosfan]

I am designing a 70'-6" high by 16'-1" wide special concentrically braced frame in the state of washington. I went with a SCBF because of the height of the warehouse. The frame supports an earthquake force of 25.0kip at the top. The dead and live loads are small. I have two columns and I have picked an HSS14x14x0.625 due to the height. There are four vertical bays of HSS4x4x0.25 bracing. The horizontal beams are W12x65. These are all preliminary sizes. The question I have regards the connection of the gusset plates and W12x65 to the tube column. In my model, I left the beam to column connection as fixed. The maximum moment is about 23kipft. Does this have to be a "qualified" connection? Can I just full penn weld the flange to the face of the column? My moment is pretty small. Also, it sounds like I have to design the brace connection for the expected yield strength of the brace (201kip). The gusset plates will probably need to be thru plated thru the column. How do you check the faces of the column for yielding? Is there a good reference anywhere? The SCBF example I'm looking at has wide flange columns. Sorry for the long post.

 

[Taro]

A few comments:

1. Your HSS14 columns do not satisfy AISC seismic compactness criteria for SCBFs.

2. Welding the beam flanges to the face of the tube column will not really be a "fixed" connection due to the flexibility of the wall. SCBFs do not rely on beam/column fixity, so just model and detail it as "pinned".

3. The AISC HSS Connections Manual (black book) is an excellent reference for connection design.