angle design

[par060]

I have a situation where I have to have an equal leg single angle that is in bending. I am using asd 89....and the appendix addresses these angles. My problem is that when I use equation (5-4)...Fob is equal to 450...this appears way to big when I try to plug it back into (5-3 a or b)...my unbraced length is 60"...and its a 3x3 1/2 angle....I just need to have a capacity to check it against....thanks for any help provided.

 

[JAE]

With an Fob = 450 (which I also calculate) you would not use 5-3a since Fob would not be less than or equal to Fy.

You would use Eq. 5-3b and with that I get Fb = 29.125 but limited by 0.66Fy = 24ksi....thus use 24 ksi

 

[par060]

thanks for the quick responce....I did come up w/ those numbers as well..the thing is that it seems even with a length term of say....300 inches....my allowable stress would be 14 ksi.....so length of the angle is not all that important