1809.6 Seismic requirements.
BC § 1809.6
For structures assigned to Seismic Design Category C or D, provisions of ACI 318 18.13, as modified by Section 1908 of this code, shall apply when not in conflict with the provisions of Section 1809 of this code. Concrete shall have a specified compressive strength of not less than 3,000 psi (20.68 MPa) at 28 days. Exceptions: 1. Group R or U occupancies of light-framed construction and two stories or fewer in height are permitted to use concrete with a specified compressive strength of not less than 2,500 psi (17.2 MPa) at 28 days.
2.One and two-family dwellings not more than three stories in height are not required to comply with the provisions of ACI 318, Section 18.11, as modified by Section 1908 of this code.
