slab - total weight estimate

Not Reviewed
Equation / Last modified by KurtHeckman on 2018/03/02 14:08
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KurtHeckman.slab - total weight estimate

The Weight of a Slab with Rebar calculator estimates the weight of a rectangular slab including rebar (if used). 

INSTRUCTIONS: Choose units and enter the following:RebarGridNew.jpg  Rebar Grid - One Mat

  • (L) The length of the slab
  • (W) The width of the slab
  • (D) The depth of the slab
  • (rS) The size of the rebar (none, 2-11,14,18)
  • (i) Rebar Inset from the edge of the slab.
  • (oC) The on-center spacing of the rebar (default 18")
  • (M) Number of rebar mats.
  • (rL) The length of the uncut rebar sticks
  • (LF) The lapping factor for rebar splices.

Weight of Slab with Rebar: The calculator returns the total weight in short tons (tons_us). However, this can be automatically converted into other weight units via the pull-down menu.

Rebar and Slab Calculators:

General Information

The volume of concrete in the slab is defined by a length, width and a depth. Furthermore, the user chooses a rebar size including “none” to indicate no rebar. For rebar spacing, the user enters an on-center value in inches (defaulted at 18") , and an inset (default 3”) to designate the distance from the side of the slab to the first courses in the rebar grid.  The user also specifies the number of mats (grids).  Based on the rebar specs, the calculator computes the length, weight and volume of rebar in the slab.  The total length of rebar is then multiplied by the pounds per inch based on the size of the rebar (3-11,14,18). The total volume of the concrete is multiplied by the unit weight constant (see constants) and the two are added together and converted to pounds or tons per the users designation. Finally, the weight is reduced by the volume of concrete displaced by any rebar.

Note: The actual weight may vary due to different types and consistencies of concrete and other factors. This equation is intended as an estimate only.