Notes to Table 4.1.8.6.:
4.1.8.9. SFRS Force Reduction Factors, System Overstrength Factors, and General Restrictions (1) Except as provided in Sentence 4.1.8.20.(7), the values of Rd
and Ro and the corresponding system restrictions shall conform to Table 4.1.8.9. and the requirements of this Subsection. (2) When a particular value of Rd is required by this Article, the corresponding Ro shall be used. (3) For combinations of different types of SFRS acting in the same direction in the same storey, RdRo shall be taken as the lowest value of RdRo corresponding to these systems. (4) For vertical variations of RdRo, excluding rooftop structures not exceeding two storeys in height whose weight is less than the greater of 10% of W and 30% of Wi of the level below, the value of RdRo used in the design of any storey shall be less than or equal to the lowest value of RdRo used in the given direction for the storeys above, and the requirements of Sentence 4.1.8.15.(5) must be satisfied. (5) If it can be demonstrated through testing, research and analysis that the seismic performance of a structural system is at least equivalent to one of the types of SFRS mentioned in Table 4.1.8.9., then such a structural system will qualify for values of Rd and Ro corresponding to the equivalent type in that Table. Table 4.1.8.9.   SFRS Ductility-Related Force Modification Factors, Rd, Overstrength-Related Force Modification Factors, Ro, and General Restrictions (1) Forming Part of Sentences 4.1.8 9.(1) and (5)  Item   Column 1   Column 2   Column 3   Column 4   Column 5   Column 6   Column 7   Column 8 

      Type of SFRS           Restrictions(2)             

          Rd   Ro   Cases Where IEFaSa(0.2)   Cases Where IEFvSa(1.0) 

                  <0.2   ≥0.2 to <0.35   ≥0.35 to ≤0.75   >0.75   >0.3 

  1.   Steel Structures Designed and Detailed According to CSA S16(3)                     

      Ductile moment-resisting frames   5.0   1.5   NL   NL   NL   NL   NL 

      Moderately ductile moment-resisting frames   3.5   1.5   NL   NL   NL   NL   NL 

      Limited ductility moment-resisting frames   2.0   1.3   NL   NL   60   30   30 

      Moderately ductile concentrically braced frames                             

      Tension-compression braces   3.0   1.3   NL   NL   40   40   40 

      Tension only braces   3.0   1.3   NL   NL   20   20   20 

      Limited ductility concentrically braced frames                             

      Tension-compression braces   2.0   1.3   NL   NL   60   60   60 

      Tension only braces   2.0   1.3   NL   NL   40   40   40 

      Ductile buckling-restrained braced frames   4.0   1.2   NL   NL   40   40   40 

      Ductile eccentrically braced frames   4.0   1.5   NL   NL   NL   NL   NL 

      Ductile plate walls   5.0   1.6   NL   NL   NL   NL   NL 

      Limited ductility plate walls   2.0   1.5   NL   NL   60   60   60 

      Conventional construction of moment-resisting frames, braced frames or plate walls                             

      Assembly occupancies   1.5   1.3   NL   NL   15   15   15 

      Other occupancies   1.5   1.3   NL   NL   60   40   40 

      Other steel SFRS(s) not defined above   1.0   1.0   15   15   NP   NP   NP 

  2.   Concrete Structures Designed and Detailed According to CSA A23.3                 

      Ductile moment-resisting frames   4.0   1.7   NL   NL   NL   NL   NL 

      Moderately ductile moment-resisting frames   2.5   1.4   NL   NL   60   40   40 

      Ductile coupled walls   4.0   1.7   NL   NL   NL   NL   NL 

      Moderately ductile coupled walls    2.5   1.4   NL   NL   NL   60   60 

      Ductile partially coupled walls   3.5   1.7   NL   NL   NL   NL   NL 

      Moderately ductile partially coupled walls     2.0   1.4   NL   NL   NL   60   60 

      Ductile shear walls   3.5   1.6   NL   NL   NL   NL   NL 

      Moderately ductile shear walls   2.0   1.4   NL   NL   NL   60   60 

      Conventional construction                             

      Moment-resisting frames   1.5   1.3   NL   NL   20   15   10(4) 

      Shear walls   1.5   1.3   NL   NL   40   30   30 

      Two-way slabs without beams   1.3   1.3   20   15   NP   NP   NP 

      Tilt-up Construction                              

      Moderately ductile walls and frames    2.0   1.3   30   25   25   25   25 

      Limited ductility walls and frames    1.5   1.3   30   25   20   20   20(5) 

      Conventional walls and frames    1.3   1.3   25   20   NP   NP   NP 

      Other concrete SFRS(s) not listed above   1.0   1.0   15   15   NP   NP   NP 

  3.   Timber Structures Designed and Detailed According to CSA O86                     

      Shear walls                             

      Nailed shear walls: wood-based panel   3.0   1.7   NL   NL   30   20   20 

      Shear walls: wood-based and gypsum panels in combination   2.0   1.7   NL   NL   20   20   20 

      Moderately ductile cross-laminated timber shear walls: platform-type construction   2.0   1.5   30   30   30   20   20 

      Limited ductility cross-laminated timber shear walls: platform-type construction   1.0   1.3   30   30   30   20    20 

      Braced or moment-resisting frames with ductile connections                             

      Moderately ductile   2.0   1.5   NL   NL   20   20   20 

      Limited ductility   1.5   1.5   NL   NL   15   15   15 

      Other wood-or gypsum-based SFRS(s) not listed above   1.0   1.0   15   15   NP   NP   NP 

  4.   Masonry Structures Designed and Detailed According to CSA S304                 

      Ductile shear walls   3.0   1.5   NL   NL   60   40   40 

      Moderately ductile shear walls   2.0   1.5   NL   NL   60   40   40 

      Conventional construction                             

      Shear walls   1.5   1.5   NL   60   30   15   15 

      Moment-resisting frames   1.5   1.5   NL   30   NP   NP   NP 

      Unreinforced masonry   1.0   1.0   30   15   NP   NP   NP 

      Other masonry SFRS(s) not listed above   1.0   1.0   15   NP   NP   NP   NP 

  5.   Cold-Formed Steel Structures Designed and Detailed According to CSA S136             

      Shear walls                             

      Screw-connected shear walls - wood-based panel   2.5   1.7   20   20   20   20   20 

      Screw-connected shear walls - wood-based and gypsum panels in combination   1.5   1.7   20   20   20   20   20 

      Diagonal strap concentrically braced walls                             

      Limited ductility   1.9   1.3   20   20   20   20   20 

      Conventional construction   1.2   1.3   15   15   NP   NP   NP 

      Other cold-formed SFRS(s) not listed above   1.0   1.0   15   15   NP   NP   NP