Monorail Flange Combined Stresses

[chrisrosebud2001]

I am looking at an under-hung monorail and am trying to verify the correct way to combine the local flange stresses with the strong and weak axis bending stresses. I am using the procedure in CMAA-74 to determine the local transverse and longitudinal stresses. I have seen several spreadsheets that indicate the total longitudinal stress to be ".75(local stress) + bending stresses". I cannot verify that this equation is correct and I was thinking that the stresses would just be additive and the local stresses not reduced by .75. Does anyone know where this reduction comes from?

 

[NOLAENG]

I see the 75% reduction in section 3.3.2.4.2 of CMAA-74. Where they got that from, who knows.