MDX Software - FAQ #17<BR><BR>

What is the difference between moment strength as shown in the LFD strength table, and moment capacity as tabulated in the LFD rating table?<br>
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Tabulated moment strength is that determined by the 
  appropriate strength expression in the specification. Moment capacity is the 
  first term in the numerator of the rating equation (6-1a) in the AASHTO Manual 
  on Condition Evaluation of Bridges. The term "capacity" is the terminology of 
  that reference, and its evaluation is as demonstrated in an example in that 
  manual. For a noncompact section, capacity is simply the product of allowable 
  stress and short term composite section modulus of the governing flange, whereas 
  strength would involve the three section moduli for noncomposite dead, 
  composite dead, and live loading. Moment strength and moment capacity   are the same for a compact section.<BR><BR></UL>