What is the minimum diameter and length of rebar to be installed in concrete at the bottom of a footing?

The correct answer indicates that the minimum diameter and length of rebar required for installation in concrete at the bottom of a footing are 1/2 inch and 20 feet, respectively. This choice aligns with standard practices in construction and engineering specifications, which dictate that the rebar must meet certain dimensions to ensure it can effectively provide the necessary tensile strength and stability to the concrete footing.

Specifically, the 1/2 inch diameter is commonly deemed sufficient for a variety of structural applications, allowing for adequate load distribution while preventing buckling or failure under stress. Additionally, a length of 20 feet is practical, as it facilitates the creation of continuous spans in the footing, minimizing weak points where the concrete might crack.

Moreover, the requirements for rebar often reflect local codes and specific structural calculations pertaining to the load-bearing capacity of the concrete elements. The selected size ensures compliance with these regulations, enabling the footing to adequately support the structure built upon it.