2107A Allowable Stress Design — 2025 Building Code (CBC)

2107 A .1 General. The design of masonry structures using allowable stress design shall comply with Section 2106 and the requirements of Chapters 1 through 8 of TMS 402 except as modified by Sections 2107 A .2 through 2107A.4.

2107 A .2 TMS 402, Section 6.1.7.1, lap splices. As an alternative to Section 6.1.7.1, it shall be permitted to design lap splices in accordance with Section 2107 A .2.1.

2107 A .2.1 Lap splices. The minimum length of lap splices for reinforcing bars in tension or compression, l d, shall be:

Equation 21 A -1 l d = 0.002 d b f s

For SI: l d = 0.29 d b f s

but not less than 12 inches (305 mm). The length of the lapped splice shall be not less than 40 bar diameters.

In regions of moment where the design tensile stresses in the reinforcement are greater than 80 percent of F s, the lap length of splices shall be increased not less than 50 percent of the minimum required length, but need not be greater than 72 d b . Other equivalent means of stress transfer to accomplish the same 50 percent increase shall be permitted. Where epoxy coated bars are used, lap length shall be increased by 50 percent.

2107 A .3 TMS 402, Section 6.1.7, splices of reinforcement. Add to Section 6.1.7 as follows:

6.1.7 – Splices of reinforcement. Lap splices, welded splices or mechanical splices are permitted in accordance with the provisions of this section. Welding shall conform to AWS D1.4. Welded splices shall be of ASTM A706 steel reinforcement. Reinforcement larger than No. 9 (M #29) shall be spliced using mechanical connections in accordance with Section 6.1.7.2.

2107A.4 TMS 402, Section 8.3.4.4 Walls.¶

Modify TMS 402, Section 8.3.4.4 as follows by adding:

8.3.4.4.1 The minimum thickness of walls is given in this section. Stresses shall be determined on the basis of the net thickness of the masonry, with consideration for reduction, such as raked joints.

8.3.4.4.2 The thickness of masonry walls shall be designed so that allowable maximum stresses specified in this chapter are not exceeded. Masonry walls shall not exceed the height or length-to-thickness ratio nor be less than the minimum thickness as specified in this chapter and as set forth in Table 8.3.4.4.

MASONRY

TABLE 8.3.4.4-MINIMUM THICKNESS OF MASONRY WALLS1, 2

*TYPE OF MASONRY*	*MAXIMUM RATIO UNSUPPORTED* *HEIGHT OR LENGTH TO THICKNESS2,3*	*NOMINAL MINIMUM* *THICKNESS (inches)*
BEARING OR SHEAR WALLS: 1. Stone masonry 2. Reinforced grouted masonry 3. Reinforced hollow unit masonry	14 25 25	16 6 6
NONBEARING WALLS: 4. Exterior reinforced walls 5. Interior partitions reinforced	30 36	6 4
1. For walls of varying thickness, use the least thickness when determining the height or length to thickness ratio. 2. In determining the height or length-to-thickness ratio of a cantilevered wall, the dimension to be used shall be twice the dimension of the end of the wall from the lateral support. 3. Cantilevered walls not part of a building and not carrying applied vertical loads need not meet these minimum requirements but their design must comply with stress and over- turning requirements.

8.3.4.4.3 Every pier or wall section with a width less than three times its thickness shall be designed and constructed as required for columns if such pier is a structural member. Every pier or wall section with a width between three and five times its thickness or less than one half the height of adjacent openings shall have all horizontal steel in the form of ties except that in walls 12 inches (305 mm) or less in thickness such steel may be in the form of hair-pins.

Exceptions & meaning →