gusset plate radius of gyration

[carnahanad]

Hello,

I'm diving deep into braced frame connection design. I'm trying to calculate my radius of gyration for a gusset plate. I know the d/sqrt(12) equation for rectangular members, I'm just not sure what to use for "d". Would it be my Whitmore length? would it be the actual length of plate connected to the beam? Would it be the longest length perpendicular to the brace within the beam? I'm pretty sure that my geometry is small enough that I'll be less than 25 per J4.4 but I want to make sure and I want to know for larger connections later.

Thanks for the help!

 

[nutte]

d = thickness

 

[JoshPlumSE]

Radius of gyration always equals sqrt (I/A).

Therefore,

r = sqrt (bt^3 / (12*A)) = sqrt (bt^3 / (12*bt))
r = t /sqrt (12)

 

[carnahanad]

Thanks.....I realized that I had my plane rotated 90 degrees in my head. This makes much more sense that d=thickness. I was all worried about the tapering of the gusset, but with the d = thickness, the tapered edges of the gusset get canceled out in the r equation and it doesn't matter. Thanks for the help!