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D1.L.1.1.4 Bending Stress

Allowable bending stress for tension and compression for a structural member, as given in XVII-2214 of NF-3000 1974 is:

  1. Along Major Axis:

  2. For Compact Sections, tension and compression on extreme fibers 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:

    Fb = 0.66×Fy  

If meeting the requirements of this member of:

  1. Width-thickness ratio of un-stiffened projecting elements of the compression flange shall not exceed 52.2/√Fy.

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

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

    d/t = (412/√Fy)[1 - 2.33(Fa/Fy)]                  

    except that it need not be less than 257/√Fy.                                          

  4. The laterally unsupported length of the compression flange of members other than box-shaped members shall not exceed the value of 76bf/√Fy nor 20000/(d/Af)Fy.

  5. For noncompact and slender elements, clause XVII-2214.2 and XVII-2214.5 of NF-3000 1974 are followed respectively.

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

    Fb = 0.60×Fy

  7. Along Minor Axis:

    For doubly symmetrical members (I shaped) meeting the requirements of XVII-2214.1(a) and (b) of NF-3000 1974, maximum tensile and compressive bending stress shall not exceed:

    Fb = 0.75×Fy