rt formula for I-shape with channel cap?
rt formula for I-shape with channel cap?
(OP)
I am looking at AISC-13th, page 16.1-51, at bottom paragraph, it read as follows:
"(ii) For I-shape with channel cap.....:
rt=radius of gyration of the flange components in flexural compression plus one-third of the web area in compression due to application of majar axis bending moment alone, in."
Can anybody help me to translate it into an exact formula, what it should look like? Does this flange components includes all the channel cap section plus the I-shape flange?
Thanks a lot for your help!
"(ii) For I-shape with channel cap.....:
rt=radius of gyration of the flange components in flexural compression plus one-third of the web area in compression due to application of majar axis bending moment alone, in."
Can anybody help me to translate it into an exact formula, what it should look like? Does this flange components includes all the channel cap section plus the I-shape flange?
Thanks a lot for your help!






RE: rt formula for I-shape with channel cap?
RE: rt formula for I-shape with channel cap?
So it is the radius of gyration of the top T-shape in Y-Y(horizontal) axis(including C-channel), not the axis Y-Y radius of gyration in Table 1-19 or Table 1-20. Right?
That will give a larger LTB capacity than use Table 1-19 or Table 1-20 ry value.
RE: rt formula for I-shape with channel cap?
RE: rt formula for I-shape with channel cap?
rT = square root of (IT / AT)
IT equals the sum of the following:
Moment of inertia of the channel
(about the channel major axis) Ix
Moment of inertia of the top flange of the beam
(tf x bf^3 / 12)
Moment of inertia of the compression portion of the web
bcw x tw^3 / 12
where bcw is the compression portion of the web.
AT is the sum of the areas of those parts.