column capacity with and without flange stiffeners
column capacity with and without flange stiffeners
(OP)
Scenario: water tower composed of braced frames. There are 4 columns, beams at 20ft in height, x-bracing at every level.
Beam to column connections are simple shear connections. Brace connections are vertical gusset plates connecting beam and brace only (this is just for discussion purposes. no brace-column connection, only relying on beam-column connection for bracing of column flange)
Question: can you develop full plastic capacity of the columns without column flange stiffeners?
assume Lp of column is > 20ft.
The beams and bracing will provide global lateral support, but the "exterior" flange does not anything connected to it. Can the "exterior" flange go plastic in strong axis bending?
Would you consider the beam-column connection to the column flange on the "inside" flange considered braced so it can go plastic in strong axis bending?
Or do I need to provide flange stiffeners at all beam locations to obtain column plastic capacity?
Beam to column connections are simple shear connections. Brace connections are vertical gusset plates connecting beam and brace only (this is just for discussion purposes. no brace-column connection, only relying on beam-column connection for bracing of column flange)
Question: can you develop full plastic capacity of the columns without column flange stiffeners?
assume Lp of column is > 20ft.
The beams and bracing will provide global lateral support, but the "exterior" flange does not anything connected to it. Can the "exterior" flange go plastic in strong axis bending?
Would you consider the beam-column connection to the column flange on the "inside" flange considered braced so it can go plastic in strong axis bending?
Or do I need to provide flange stiffeners at all beam locations to obtain column plastic capacity?






RE: column capacity with and without flange stiffeners
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: column capacity with and without flange stiffeners
what are your thoughts if this were not a seismic location?
RE: column capacity with and without flange stiffeners
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: column capacity with and without flange stiffeners
Thanks for discussing.
Does anyone else have any additional thoughts?
RE: column capacity with and without flange stiffeners
It might also be worth examining AISC's design guide on end plate moment connections. Many of those are unstiffened and develop heavy column moments. They offer more restraint than clip angles but not tonnes more.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.