I am modeling simple-span steel beams with a non-composite concrete deck. What formulas should I be using to calculate the LRFD distribution factors? I note that when I let LARS calculate the factors, the factors calculated when I model it as CSC are different than when I model it as SS. The AASHTO LRFD Bridge Design Specifications Table 4.6.2.2.2b-1 does not appear to address steel stringers with a non-composite deck. The factors that LARS calculates for the CSC model agree with the formula for composite concrete deck in the table. I cannot figure out what formula is being used by LARS for the SS model.