Seismic Design Requirements ...continued

Seismic Performance Category D

Structures in Seismic Performance Category D shall comply with the requirements of Seismic Performance Category C and to the additional requirements of this section.

Minimum reinforcement requirements for masonry walls - Masonry walls other than those covered by Section 10.5.2.3 shall be reinforced in both the vertical and horizontal direction. The sum of the cross-sectional area of horizontal direction. The sum of the cross-sectional area of horizontal and vertical reinforcement shall be at least 0.002 of the cross-sectional area of the wall, and the minimum cross-sectional area in each direction shall be not less than 0.0007 times the gross cross-sectional area of the wall. Reinforcement shall be uniformly distributed.

Shear wall reinforcement requirements - The maximum spacing of vertical and horizontal reinforcement shall be the smaller of, one-third the length of the shear wall, one-third the height of the shear wall, 48 in. (1219 mm).

Seismic Performance Category E

Structures in Seismic Performance Category E shall comply with the requirements of Seismic Performance Category D and to the additional requirements of this section.

Design of elements that are not part of lateral force resisting system - Stack bond masonry that is not part of the lateral force-resisting system shall have a horizontal cross-sectional area of reinforcement of at least 0.0015 times the gross cross-sectional area of masonry. The maximum spacing of horizontal reinforcement shall be 24 in. (610 mm). These elements shall be solidly grouted and shall be constructed of hollow open-end units of two wythes of solid units.

Design of elements that are part of the lateral force resisting system - Stack bond masonry that is part of the lateral force- resisting system shall have a horizontal cross-sectional area of reinforcement of at least 0.0025 times the gross cross-sectional area of masonry. The maximum spacing of horizontal reinforcement shall be 16 in. (406 mm). These elements shall be solidly grouted and shall be constructed of hollow open-end units or two wythes of solid units.