Laserfiche WebLink
Concrete stabs -on -grade should have a minimum nominal thickness of 4 inches. Minimum <br />reinforcement for concrete slabs -on -grade should be No. 3 deformed reinforcing bars, spaced at 12 <br />inches <br />do- center each way. Additidnal reinforcing and/or slab thickness should be *provided as <br />structural conditions dictate. <br />If approved by the owner, equivalent welded wire mesh may be used for reinforcement of concrete <br />slabs -on -grade. However, to be effective it is imperative that the reinforcement be located within <br />the center third of the slab thickness. The commonly used procedure of "hooking" the <br />reinforcement during concrete placement seldom, if ever, results in proper location of the slab <br />reinforcing. <br />To protect dgainst capillary moisture from the underlying, the building floor slab in areas that are <br />to be covered by carpet, tile or other moisture sensitive floor coverings should be underlain by a <br />minimum 6 -mill plastic membrane covered with a minimum of two inches of sand. In lieu of a <br />plastic membrane and sand, a 4 -inch thick layer of open graded gravel may be used. <br />A suggested gradation for the gravel layer is as follows: <br />Sieve Size Percent Passing <br />3/4 90-100 <br />No. 40 0-10 <br />No. 100 0-3 <br />Other design and construction criteria for concrete floor slabs, such as mix design, strength and <br />durability, reinforcement and joint spacing, etc., should conform to current specifications <br />promulgated by the American Concrete Institute (ACI). <br />Structural design for resistance of lateral forces may be based upon a lateral earth pressure of <br />400 pounds per square foot per foot of depth and a coefficient of friction between concrete and <br />compacted fill or native soil of 0.2. <br />rx 4=7.095-01 <br />u s 7-06t-\sft�.a- <br />6-2 <br />