Posted by CMPC on October 22, 1999 at 12:58:20:
In Reply to: Control Joint Locations for Type II Units posted by David M. Sammons, P.E. on October 20, 1999 at 13:15:59:
The National Concrete Masonry Association recently published their TEK note #10-2A which describes a new design methodology for control joints. This methodology is called the crack control coefficient (CCC). This coefficient is not based on whether you have a type I or type II masonry unit but simply on the absorption rate of the CMU. Additional criteria such as how much horizontal joint reiforcement you design for and the effect of carbonation (shrinkage due to the reaction of carbon and cementitious material) are taken into consideration. The distance between control joints is then determined by including the coefficient into a simple formula. For more information contact the NCMA at www.ncma.org or refer to the movement control case study found at this web site.