Jx and Jy Section Properies

[hytham2311]

Hello, does anyone know a program or spreadsheet or what ever to calculate jx and jy torsional constants ? this is related to calculating punching shear for corner column according to aci 421

 

[r13]

Are you sure the terms are not Ix and Iy?

 

[Blackstar123]

The J term used in punching shear equation is not the torsional constant, but the sum of moment of inertias of faces resisting the shear.

For example, for an interior column with punching area b1xb2, depth d and, a moment applied about an axis parallel to b2. J will be calculated as:
J = 2x(d b1^3/12) + 2x(d b2 (b1/2)^2) + 2x(b1 d^3/12)

The first two terms are for resisting shear parallel to d and the third term is for the shear transverse to d. This is why, "J" is termed as analogous to polar moment of inertia.

 

[Agent666]

Check here for some derivations.