The LRFD 4th Edition with 2009 interim revisions introduced the Fatigue I limit state and allowable compression stress limits (LRFD 5.5.3.1). The LRFD specification says "The section properties for fatigue investigations shall be based on cracked sections where the sum of stresses, due to unfactored permanent loads and prestress, and the Fatigue I load combination is tensile and exceeds 0.095(f'c)^0.5. PGSuper deviates from the prescribed method of calculation in that it always uses uncracked section properties.