All About Choosing Rebar and Rebar Bending Machinery

Concrete reinforcing steel is commonly known as rebar and is used in concrete and masonry structures. It is usually formed from carbon steel and is given ridges for better mechanical anchoring into the concrete. The ridges help transfer the load between concrete and steel. Concrete provides the material’s compressive strength, while steel, in the form of embedded reinforcing bars, provides tensile strength. These two materials used together stop a concrete block from crumbling. If you recall the devastation of the last large earthquake in Mexico City it was the new buildings that collapsed while the older structures endured. This is because the new buildings didn’t use rebar, but only smooth solid bar. There was no compression strength given to the concrete.

Rebar is measured in fractions of 1/8 increments. They range from #3 bar up to #18 bar. So, a #4 bar is 4/8 or ½” in diameter and a #8 bar is 1″ in diameter. Rebar is available in different grades and specifications that vary in yield strength, ultimate tensile strength, chemical composition, and percentage of elongation.

The grade designation is equal to the minimum yield strength of the bar. For example, grade 40 rebar has a minimum yield strength of 40ksi, grade 60 a minimum yield of 60ksi, and grade 75 a minimum yield of 75ksi. Most rebar used for concrete construction is grade 60. For residential rebar use, which is mostly for sidewalks and low stress concrete construction, grade 40 is used. We find grade 75 used in power plants, bridges, and other heavy duty concrete products.

Since rebar generally comes in 20′ length sticks there must be a way to fabricate these bars. By this we mean shearing and bending to conform to the engineers drawings. Rebar shears and benders come in a multitude of sizes. The capacities are related to the bar size as mentioned above. If a residential concrete mason works with #3 through #6 bar they will usually source a machine that can cut and bend #8 bar as sometimes they will process more than one bar at a time in order to speed up production, so the extra capacity is very helpful.

For heavy concrete construction, it is even more important to determine the correct capacity when selecting the equipment. The bar diameter used when erecting buildings and bridges increases as does the grade of steel, requiring machines of heavier capacity. It is very important to work with a supplier who is knowledgeable and experienced and will assist you in determining the correct capacity of the machine for your application.