Document Information

Document Type: FAQ

Product(s): LEAP BRIDGE STEEL

Version(s): All

Original Author: Bentley Technical Support Group -VM

QUESTION: How is the program calculating Δf  -- Fatigue stress range and the related Performance Ratio?

ANSWER:

Δf = fatigue stress range.

Delta_f = (Mzp – Mzn) * Ybar_bottom_of_the_web / Iz

Mzp = Max positive moment

Mzn = Max negative moment

 Performance ratio = 0.75*4.192 / 1.924 = 1.634