Q. What is a structural slab on ground (grade)?
A "structural slab" on ground uses a composite of concrete and structural steel to support the design load. Structural steel may be "rebar" or welded-wire fabric (WWF) where the cross sectional area of the steel specified is used in determining the load capacity of the slab.

The thickness/depth of a structural slab is based on the quantity of rebar or WWF included in the cross-section. ACI 301-Standard Specifications for Structural Concrete is the method used to design this type of slab.

Synthetic or steel fibers may be used in the composite to reduce plastic and hardened concrete shrinkage. Steel fibers may be used to provide shrinkage reinforcement at low dosage levels or enhance flexural strength at higher dosage levels.

Projects that require extremely high or abnormal load forces, or where the number of load cycles per time increment is high, will use structural slabs. In some cases, steel fiber may be used for these applications, especially where durability properties come into play like impact surface abrasion and fatigue.

Structural slabs are used where the dynamic or static loads would make the use of a plain concrete slab impractical due to the thickness of the slab that would be required. Structural slabs are usually found at industrial sites where heavy repetitive loads would be typical.

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