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.

　　為了結構或者構件需要滿足一定的強度保證率，原材料的強度不可能都是同一的強度，有的可能高點，有的低點，假如鋼筋抗拉強度設計值是210兆帕的話，在100根鋼筋里面，有95根強度在210以上，只有5根低于210，這就是滿足95%保證率的要求。

　　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.

　　受拉鋼筋設計時是按屈服強度設計都是以屈服強度為標準定的，屈服強度部分受拉和受壓，屈服強度都是一樣，比如Q235的鋼筋，設計值就是235，標準值就是210，Q335的鋼筋，設計值是335。標準值主要是計算承載力的，設計值使用來驗算結構或構件的撓度和裂縫寬度的。

　　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.