2121.2.3 Tie Beams
Unless otherwise required by design, all tie beams shall have four #3 ties at 12 inches (305 mm) on center. at corners and at each bend and at 48 inches (1219 mm) on center elsewhere. A tie beam shall be not less in dimension or reinforcing than required for the conditions of loading nor less than the following minimums: a tie beam shall have a width of not less than a nominal 8 inches (203 mm), shall have a height of not less than 12 inches (305 mm) and shall be reinforced with not less than four #5 reinforcing bars placed two at the top and two at the bottom of the beam except that a tie beam using "U" type beam block may be used with the following limitations:
- Limited to one-story Group R-3 occupancy.
- Limited to unsupported spans of 7 feet (2.1 m).
- Beam block shall be reinforced with one #7 bar in the top and one #7 bar in the bottom of the pour.
- Beam block shall provide not less than 14 inches (356 mm) vertical dimension or less than 41/2 inches (114 mm) horizontal dimension of poured-in-place beam cross-section.
- Where beam blocks are used, consideration of resistance to uplift caused by wind forces shall be based on only that portion of the dead load above the topmost mortar joint in the wall.