Rebar Standard, Grades, Size and Length

What is the difference between YIELD STRENGTH & TENSILE STRENGTH?

Learning about rebar grades is necessary and it's also crucial to understand what is being measured. This includes both tensile strength and yield strength. Tensile strength refers to the maximum stress that a material can withstand before it breaks when stretched or pulled. It is measured in pounds per square inch (psi) or megapascals (MPa). Yield strength is the stress at which a material begins to deform, and it is also measured in units of force per unit area, such as psi or MPa.

In the Philippines the sizes, lengths, grades of reinforcing steel is adhere to Philippine National Standard (PNS 49:2020). As well as the global ASTM Standard (ASTM A615/A706) established by the American Society for Testing and Materials (now known as ASTM International).

Rebar grades are set by ASTM. The grade designation is equal to minimal yield strength in kilo pounds per square inch (KSI). Common grades are 40, 60, 75, 80, and 100. The nomenclature for the grades represents how much yield the rebar has. For example, grade 40 rebar has a minimum yield strength of 40 KSI, which is equal to 40,000 PSI, whereas grade 80 rebar has a minimum yield strength of 80 KSI or 80,000 PSI.

Rebar grade are embossed on the bars in addition to different color markings painted at the end of each bar, as shown in the following table:

Rebar size refers to the cross-sectional area of a reinforcing bar, expressed in square millimeters or square inches. The size of the rebar is an indicator of its strength and is specified by building codes and engineering standards.

Rebar diameter, on the other hand, refers to the thickness of the bar, expressed in millimeters or inches. The diameter of the rebar is a crucial factor in determining its strength, and it is usually related to the rebar size, with larger rebar sizes having larger diameters.