Cold-rolled ribbed steel bar is an updated product of cold-drawn low-carbon steel wire in prestressed concrete members. In the cast-in-place concrete structure, I-grade steel bars can be used instead to save steel, which is a better kind of cold-worked steel of the same kind.
The grade of cold-rolled ribbed steel bar consists of CRB and the minimum tensile strength of steel bar. C, R and B are the initials of the words cold-rolled, ribbed and reinforced respectively.
Cold rolled ribbed steel bars are divided into CRB550, CRB650, CRB800 and CRB970. CRB550 is reinforced for ordinary reinforced concrete, and other brands are prestressed concrete reinforcement.
Extended data
Advantages of cold-rolled ribbed bar:
1, the steel strength is high, which can save steel for construction and reduce the project cost. Compared with hot-rolled round steel, LL550 cold-rolled ribbed steel bars can save 35%-40% steel when used in cast-in-place structures (especially building roofs).
You will save more steel if you consider not using hooks. According to the steel market price, every ton of cold-rolled ribbed steel bars can save the steel cost about 800 yuan.
2. The bonding and anchoring performance between cold-rolled ribbed steel bars and concrete is good. Therefore, when used in members, the phenomena of cracking in the anchorage zone of members and steel wire sliding are fundamentally eliminated, and the bearing capacity and crack resistance of the end of members are improved; In reinforced concrete structures, the crack width is also smaller than that of round steel, even smaller than that of hot-rolled threaded steel bars.
3. In the cast-in-place concrete structure of residential buildings and various public buildings, the elongation of cold-rolled ribbed steel bars is greater than that of similar cold-worked steel bars.
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