Question: In a strength analysis, should I include the flutes in a fluted block wall?

Answer:In its technical note 77, "Properties of Customized Architectural Concrete Masonry," The National Concrete Masonry Association (NCMA) describes procedures for taking the ribs into account in engineered masonry design. These procedures can be used only if the flutes are completely bedded in mortar. If they are, the area of the flutes may be included in both bending and axial load calculations. If flutes are considered in the calculations, the fluted block must be treated as a nonsymmetrical unit.According to this technical note, flutes also may be used to determine wall thickness for empirical design--but only if they are completely bedded in mortar and if walls span vertically between lateral supports. If either of these requirements isn't met, the flutes should be disregarded in design.