I have a typical chevron braced fou

[structengr23]

I have a typical chevron braced four level industrial structure that’s 10’ x 16’ base with four W12x65 columns. Supports a vertical vessel supported at the third level.

I’ve got a base plate with six bolts, three each outside the flanges. Since there’s a bolt at the center of the flange, I’m not able to grab the baseplate the the bottom of my gussets. My brace load is only about 20 kips, but I’m hung up with stopping my gusset above my anchor bolt. I modeled the work point one foot above the baseplate and ran my RISA model with this vertical offset and column is good. RISA connection is good with just a typical vertical brace connection, not connecting to the baseplate. Any reason to necessarily connect to the baseplate with a straddle type stiffened seat? Probably over thinking it.

 

[WARose]

Any reason to necessarily connect to the baseplate with a straddle type stiffened seat?

If you've accounted for the offset in the model (and ergo the calculations).....probably not. However, if this is going into the weak axis of the column (and it sounds like it isn't), when the shop drawings come in, check the web of the column with the thrust component of the brace load.

Aside from that, if you've accounted for all the forces (and you've got the necessary wrench clearances).....sounds ok to me.

 

[structengr23]

WARose...thanks for the quick feedback. That’s my thinking as well, just needed feedback from another source. This is in the major axis direction. In the minor axis, my gusset grabs plenty of baseplate and web, since I don’t have a middle anchor in that direction.

We use standard connection details, so we have one for a major axis vertical brace with a vertical work point offset. I will use that, but I will definitely review the shop drawings to make sure I get the gusset length and geometry that I want.

 

[canwesteng]

When I've done this into the weak axis of the column I show a stiffener stopping short of the bolt hole to be incorporated into the gusset. Wouldn't need it in your case, but I might put a note on the base plate drawings with how much clearance you want above the hole.