How do I design a moment frame in the weak axis? Staad is "failing" sections that were designed in a previous command for "Select Members". Why?

Question

QUESTION 1: 
 I am designing a 12-storey building using Staad Pro v8i. I have moment frames going in both East-West and North-South directions. The frames in the E-W direction are to be designed per the strong axis due to wind load considerations. How do I design the frame in the N-S direction so that Staad Pro designs this and checks for stresses and other criteria in the minor axis of the column? 
 
 I know that there is an option of "Axis" in the design parameters' but this is just for single angles and not "W" columns. 
 QUESTION 2: 
 While designing the frames for this building; I am performing an initial "Check Code" to check for the sections that I have designed using ENERCALC. After this; I am asking Staad to design the same sections using AISC 1989 ASD code. Finally I am asking Staad to check the design it suggested. In this case; Staad is failing the same beams/columns that it just designed in the previous parameter? Can you let me know what is going on here? 
 QUESTION 3: 
 I am adding bracing to the moment frame in this building. These are added as 4'x4' knee braces at the ceiling level; and specified as truss members. While performing seismic analysis; Staad is failing these bracing and showing the joints as unstable. Why is it failing these joints? Also, it is performing checks per equation H1-1, H1-2 and H2-1 on these members. I have specified these as truss members and hence they should not take any moment. Staad is still checking these for the above equations. Can you let me know the reason for this failure? 
 
 Thank you.

Seth Guthrie · Accepted Answer

1. You don't have to do anything special to have the weak axis of the column checked in a space frame model. Do be careful assigning the K factors, however. 
 2. Once the member size is changed, a subsequent analysis may result in larger forces for the modified member because the stiffness matrix has changed. This could fail the member requiring yet a larger size. A few iterations is usually enough to level things. 
 3. Make sure you don't have any loads applied directly to the truss members. We sometimes recommend a weightless material (or just don't assign self weight) to prevent bending in truss members. If that's not the cause of your issue then please share your model (there is a Secure File upload link on the right if you don't want to share publically)

Seth Guthrie · Answer

1. I recommend a space frame if you are really dealing with corner columns in frames for both directions. 
 2. Check out the SELECT OPTIMIZED command. 
 3. If you look at the Post Processing screen you'll see the knee braces flying off into space. This happens because the beams and columns are bypassing the nodes leaving the braces unsupported. As such the whole analysis is not right. 
 There are a number of ways to split the beams where the braces intersect. I used Geometry - Break Beams at Selected nodes (with all of the beams, columns, braces and nodes on the right selected).