The most stringent applicable structural system limitations contained in Table 12.2-1 is applied by users.


12.2.3 Combinations of Framing Systems in the Same Direction

If different seismic force-resisting systems are used in combination in the same direction, the most stringent applicable structural system limitations contained in Table 12.2-1 is applied.

The intent of the provision requiring use of the most stringent seismic design parameters (R, Ω0, and Cd) is to prevent mixed seismic force-resisting systems that could concentrate inelastic behavior in the lower stories.

12.2.3.3 R, Cd, and Ω0 Values for Horizontal Combinations

The value of the response modification coefficient, R, used for design in the direction under consideration is not greater than the least value of R for any of the systems used in that direction. The deflection amplification factor, Cd, and the overstrength factor, Ω0, is consistent with R required in that direction.