Allowable bending stress for tension and compression for a structural member, as given in NF-3322.1(d) is:

1. Along Major Axis:

   1. For Compact Sections, tension and compression on extreme fibres of compact hot rolled or built-up members symmetrical about and loaded in the plane of their minor axes and meeting the requirements of Subsection NF shall result in a maximum bending stress:

      F_b = 0.66×F_y

      If meeting the requirements of this member of:

      1. Width-thickness ratio of unstiffened projecting elements of the compression flange shall not exceed 65/√F_y .

      2. Width-thickness ratio of stiffened elements of the compression flange shall not exceed 190/√F_y .

      3. The depth-thickness ratio of the web shall not exceed

         d/t = (640/√F_y)[1 - 3.74(f_a/F_y)] when f_a/F_y ≤ 0.16

         d/t = 257/√F_y when f_a/F_y > 0.16

      4. The laterally unsupported length of the compression flange of members other than box-shaped members shall not exceed the value of 76b_f/√F_y nor 20,000/(d/A_f)F_y .

   2. For noncompact and slender elements, NF-3322.1(d)(5) and NF-3322.1(d)(3) are followed respectively.

   3. For box-type flexural members, maximum bending stress is:

      F_b = 0.60×F_y

2. Along Minor Axis:

   1. For doubly symmetrical members (I shaped) meeting the requirements of NF-3322.1(d)(1)(a) and (b), maximum tensile and compressive bending stress shall not exceed:

      F_b = 0.75×F_y

   2. For doubly symmetrical members (I shaped) meeting the requirements of NF-3322.1(d)(1)(a), except where b_f/2t_f exceeds 65/√F_y but is less than 95/√F_y , maximum tensile and compressive bending stress shall not exceed:

      F_b = F_y[1.075 - 0.005(b_f/2t_f)√F_y]