There is a design value called the design value of tensile strength of reinforcing steel bar, and there is a word called standard value. As you can imagine, these two values must be in order to ensure their safety, and come out of a numerical value, today I will tell you what these two are.
For the sake of structure or component safety, the strength of raw materials can not be the same strength, some may be high, some low, if the design value of steel bar tensile strength is 210 MPa, 95 of the 100 steel bars have strength above 210, only 5 of them are below 210, which is to meet the requirement of 95% guarantee rate.
Tensile steel bars are designed according to yield strength. The yield strength is partly tension and compression, and the yield strength is the same. For example, Q235 steel bars, the design value is 235, the standard value is 210, Q335 steel bars, and the design value is 335. The standard value is mainly used to calculate the bearing capacity, and the design value is used to check the deflection and crack width of the structure or component.