The Rebar and Concrete in a Slab calculator computes the total length and weight of rebar and the volume of concrete needed for a slab.
INSTRUCTIONS: Choose units and enter the following:
Rebar and Concrete in a Slab: The calculator returns:
However, the above can be automatically converted to compatible units via the pulldown menu.
See the Rebar Calculator for more concrete and rebar functions and features. VIDEO INSTRUCTION
The rebar algorithm calculates the length of rebar in the grid based on the slab dimensions, spacing, inset, number of mats, rebar size and lapping factor. Based on the rebar length and size, the weight of rebar is computed. Based on the slab dimensions and the volume displaced by rebar, the volume of concrete is computed.
Reinforcement bars are often used in concrete including common slabs. This formula provides a length and weigh calculation that is useful in understanding the additional load of the slab added by the rebar steel. It is also useful for calculating the weight of rebar when considering transport. Steel is dense and heavy. Most vehicles would be considerably overloaded in weight of rebar long before their potential volume is full, which poses a significant safety issue. In the U.S., most pickup trucks are rated at a half or three quarters ton load rating. This rating indicates the safe weight of a load that can be carried. The rebar weight formula can help determine how many trips are required to transport the load of reinforcement steel safely.
This is useful for:
When the dimensions of your slab or wall exceed the length of a single piece of rebar, it is required to lap bars and tie them to create the added length. There are a few considerations. First, the length of the lap is often specified as 40 times the diameter of the rebar. In this case, 40 is lapping factor. 60 is also a common factor, but the engineering specifications should always be applied. See these YouTube videos to better understand rebar lap:
Second, the typical length of pre-cut rebar is 40' and 60' in the United States.