huangyhg

torsion on a loose lintel supporting brick
i am trying to check the torsion of a loose lintel vs the bia-recommended limit of 1/16"....but i can't find the "j" of steel angle shapes for my t*rho/j formula. does anyone know where i can find j of angles? can i just take j=ixx+iyy?
thanks

i can't re
the aisc manual has a table of torsional properties for hot-rolled shapes. see part 1 of the third edition lrfd, part 1 of the ninth edition asd, or aisc design guide 9. if you are outside of the us, you'll have to check your own references and manuals, but it shouldn't be a mystery.
note that ix+iy is the polar moment of inertia, not the torsion constant.
i didn't see j in part 1 of 2nd ed'n or 3rd ed'n of lrfd or j in asd...j's not in there.
begin on page 1-117 of the 9th edition asd or 1-89 or the 3rd edition lrfd.
ah! gotcha...thank you
for open sections (such as angles), the torsional constant j is equal to (1/3)*the sum of b*t^3 of all the pieces.

__________________
借用达朗贝尔的名言：前进吧，你会得到信心!
[url="http://www.dimcax.com"]几何尺寸与公差标准[/url]