What's the difference between the steel design codes for Ram Frame? I'm noticing that my model will run without failures and with significantly lower unity check numbers under AISC-ASD than any other code I select. Any idea why this would be happening? I always thought LRFD would give more precise numbers and that ASD was more conservative in the design process.
ASD is not always more conservative. The load factors are not the same for Dead and Live loads in LRFD so there is a single ratio of dead to live load that will balance out phi vs. Omega. You might want to review the code commentary for chapter B.
For frame design, it's also important to use factored, or strength level demand gravity loads in the P-Delta analysis even when using ASD. See our AISC 360 Direct Analysis wiki for details: communities.bentley.com/.../4426.aspx