...
A redundancy factor, ρ, is used to the seismic force-resisting system in each of two orthogonal directions for all structures in accordance with Eq. 12.4-3.
...
According to 12.3.4.1 - ρ is 1.0
Structures assigned to Seismic Design Category B or C
Drift calculation and P-delta effects
Design of collector elements, splices, and their connections for which the seismic load effects, including overstrength of Section 12.4.3, are used
Design of members or connections where the seismic load effects, including overstrength of Section 12.4.3, are required for design
Diaphragm loads determined using Eq. (12.10-1), including the limits imposed by Eqs. (12.10-2) and (12.10-3)
Structures with damping systems designed in accordance with Chapter 18
Design of structural walls for out-of-plane forces, including their anchorage
12.3.4.2 Redundancy Factor, ρ, for Seismic Design Categories D through F
For structures assigned to Seismic Design Category D and having extreme torsional irregularity as defined in Table 12.3-1, Type 1b, ρ is equal 1.3.
...