TM 5-809-3/NAVFAC DM-2.9/AFM 88-3, Chap. 3
open-end units allows placement of the vertical reinforcing steel with a minimum number of splices--thus
vertical reinforcement can usually be continuous between supports. The vertical alignment of webs in open-
end units provide large open cells that can be easily grouted. The grouted open-end cells provide good load
transfer and allow for complete grouting of lintels and beams. Masonry units with three webs often have
concave ends which makes it difficult to fully grout a wall. Therefore, when three web units are used in
lintels, masonry beams, and fully grouted walls, grouting at each course level is required.
b. Section properties of reinforced masonry.
(1) Assumed concrete masonry unit dimensions. As a general rule, the dimensions for hollow CMU
may be assumed as shown in figure 5-2 and given in table 5-1. These values will vary with unit type,
geographic location, and manufacturer; however; they are considered conservative--thus were used in the
design calculations in this manual.
(2) Equivalent wall thickness. The equivalent thickness for masonry walls with hollow units and varying
grouted cell spacings will be as shown in table 5-2.