Control Joints

[JStructsteel]

Have a slab where I would end up with 12'x17' sections. Would you cut that down to 12'x8' for the control joints? 4" thick slab. 12x12 wire mesh in it.

 

[Enable]

Pretty much. Aspect ratio should be kept at a maximum of 1.5 so 12'x8' will work (probably cut that bad boy in half so 12'x8.5')

The aspect ratio of slab panels that are unreinforced, reinforced only for shrinkage and temperature, or made with shrinkage-compensating concrete should be a maximum of 1.5 to 1; however, a ratio of 1 to 1 is preferred. L- and T-shaped panels should be avoided. Plastic or metal inserts are not recommended for constructing or forming a contraction joint in any exposed floor surface that will be subjected to wheeled traffic.

https://www.concrete.org/Portals/0/Files/PDF/302.1R-15_Chapter5.pdf