What are the most current references and programs to use for the design of a four story structure with upper 3 stories for parking in a seismic zone 4 (1997 UBC). We are considering a post-tensioned concrete structure with concrete shear walls. We will have occupied space on the first level with 40-55 foot clear spans. What computer programs would be recommended to use for the design of the post-tensioned members? Are post-tensioned beams the appropriate choice for this type of structure? Are structural Tees readily available? Any good references about the design of parking structures in seismic zone 4? All comments and recommendations are welcome and will be appreciated!