AASHTO Load Cases

[soukup73]

Does anyone know what the standard governing load factors are for concrete bridge slabs designed with AASHTO LRFD? I have read that it is 1.3DL + 2.17LL and I have also seen 1.25DL + 1.75LL listed. And I have even seen 1.3DL + 1.3LL. Which of these is the latest governing load case in the current AASHTO LRFD? Again, this is for a check on a concrete bridge slab.

On another note, is the phi factor calculated as it is for regular LRFD for concrete (steel strain above 0.005, than phi = 0.9)?

 

[Dinosaur]

THe first factored load equation appears to be from previous editions of AASHTO (1990s era). It is the one I used when I was desinging bridges. I believe the second equation may be the correct one in the LRFD specs. I don't have a copy of the LRFD so I can't check that out.

Phi = 0.9 sounds correct.

Good Luck.

BTW, there is a bridge engineering forum here also.