2106A Seismic Design — 2025 California Building Code
California Building Code (Title 24, Part 2) · 2025 edition · updated 2026-09-25 · California
CBSC: official editions, supplements and errata
Italicized text is a California amendment to the model code, as printed in the official publication.
Cite as: 2025 California Building Code (Title 24, Part 2) § 2106A · Effective January 1, 2026 · Official source: Building Standards Commission
2106 A .1 Seismic design requirements for masonry. Masonry structures and components shall comply with the requirements in Chapter 7 of TMS 402 depending on the structure’s seismic design category.
2106A.1.1 TMS 402, Section 5.4.1.4. Replace TMS 402, Section 5.4.1.4 Items (a), (b), (d) & (e) by the following: (a) Vertical reinforcement shall be enclosed by lateral ties at least 3/8 in. ( 9.5 mm ) in diameter. (b) Vertical spacing of lateral ties, over the full height of the column, shall not exceed 8 longitudinal bar diameters, 24 lateral tie bar diameters, 8 inches (203 mm), or one-half the least cross-sectional dimension of the member. (d) Lateral ties shall be embedded in grout. (e) Lateral ties shall be located vertically not more than one-half lateral tie spacing above the top of the footing or slab in any story, and shall be spaced not more than one-half a lateral tie spacing nor 2 inches (51 mm) below the lowest horizontal reinforcement in beam, girder, slab, or drop panel above. The top tie shall be within 2 inches (51 mm) of the top of the column.
2106A.1.2 TMS 402, Chapter 5. Add TMS 402, Section 5.7 as follows:
5.7 – Lateral Support of Members
5.7.1 – Lateral support of masonry may be provided by cross walls, columns, pilasters, counterforts or buttresses where spanning horizontally, or by floors, beams, girts or roofs where spanning vertically. Where walls are supported laterally by vertical elements, the stiffness of each vertical element shall exceed that of the tributary area of the wall.
21A-8 2025 CALIFORNIA BUILDING CODE
MASONRY
2106A.1.3 TMS 402, Section 7.3.2.5 (i). Replace first sentence of TMS 402, Section 7.3.2.5 (i) by the following: (i) When the ratio of V/F vm A mv for masonry designed in accordance with Chapter 8 or when the ratio V u /ΦV nm for masonry design in accordance with Chapter 9 exceeds 0.15, or the h w /l w exceeds 0.5, the termination of horizontal reinforcement embedded in grout shall meet one of the following:
2106A.1.4 TMS 402, Sections 7.4.4.1 and 7.4.5.1. Replace TMS 402, Section 7.4.4.1 as follows and delete Section 7.4.5.1:
7.4.4.1 Minimum reinforcement requirements for masonry walls. The total area of reinforcement in reinforced masonry walls shall not be less than 0.003 times the sectional area of the wall. Neither the horizontal nor the vertical reinforcement shall be less than one third of the total. Horizontal and vertical reinforcement shall be spaced at not more than 24 inches (610 mm) center to center. Where other than running bond is used in reinforced hollow unit masonry, the open-end type of unit shall be used with vertical reinforcement spaced a maximum of 16 inches (406 mm) on center.
Exception: Reinforced hollow unit masonry used for freestanding site walls or interior nonbearing nonshear wall partitions shall have horizontal reinforcing spaced not more than 4 feet (1.2 m) on center, except for locations in Seismic Design Category F, and may be grouted only in cells containing vertical and horizontal reinforcement.
7.4.4.1.1 The minimum reinforcing shall be No. 4, except that No. 3 bars may be used for ties and stirrups. Vertical wall reinforce- ment shall have dowels of equal size and equally matched spacing in all footings. Reinforcement shall be continuous around wall corners and through intersections. Only reinforcement which is continuous in the wall shall be considered in computing the minimum area of reinforcement. Reinforcement with splices conforming to TMS 402 shall be considered as continuous reinforcement.
7.4.4.1.2 Horizontal reinforcing bars in bond beams shall be provided in the top of footings, at the top of wall openings, at roof and floor levels, and at the top of parapet walls. For walls 12 inches (nominal) (305 mm) or more in thickness, horizontal and vertical reinforcement shall be equally divided into two layers, except where designed as retaining walls. Where reinforcement is added above the minimum requirements, such additional reinforcement need not be so divided.
7.4.4.1.3 In bearing walls of every type of reinforced masonry, there shall be trim reinforcement of not less than one No. 5 bar or two No. 4 bars on all sides of, and adjacent to, every opening which exceeds 16 inches (406 mm) in either direction, and such bars shall extend not less than 48 diameters, but in no case less than 24 inches (610 mm) beyond the corners of the opening. The bars required by this paragraph shall be in addition to the minimum reinforcement required elsewhere.
7.4.4.1.4 When the reinforcement in bearing walls is designed, placed and anchored in position as for columns, the allowable stresses shall be as for columns.
7.4.4.1.5 Joint reinforcement shall not be used as principal reinforcement in masonry.
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