Modification Factor1
Number of Stories
1
1
2
1.2
3
1.3
5
1.4
10+
1.5
1. Linear interpolation should be used to calculate intermediate values.
Table 5-1: Values for Modification Factor C0
T = 0.1 second
T >= Ts second
Performance Level
Type11
2
1
Type 22
Type 2
Type 1
Immediate Occupancy
1.0
1.0
1.0
1.0
Life Safety
1.3
1.0
1.1
1.0
Collapse Prevention
1.5
1.0
1.2
1.0
1.
Structures in which more than 30% of the story shear at any level is resisted by components or elements whose strength and stiffness may
deteriorate during the design earthquake. Such elements and components include: ordinary moment-resisting frames, concentrically-braced
frames, frames with partially-restrained connections, tension-only braced frames, unreinforced masonry walls, shear-critical wall and piers, or
any combination of the above.
2.
All frames not assigned to Framing Type 1.
Table 5-2: Values for Modification Factor C2
5-16
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