1) Nominal diameter range and recommended diameter
The nominal diameter of steel bars ranges from 6 to 50mm, and the standard recommended nominal diameters of steel bars are 6, 8, 10, 12, 14, 16, 20, 25, 32, 40, and 50mm.
2) The allowable deviation of the surface shape and size of the ribbed steel bar
The design principles of transverse ribs of ribbed steel bars shall meet the following requirements:
The angle β between the transverse rib and the axis of the steel bar should not be less than 45 degrees. When the included angle is not greater than 70 degrees, the direction of the transverse ribs on the opposite sides of the steel bar should be opposite;
The nominal spacing l of transverse ribs shall not be greater than 0.7 times the nominal diameter of the steel bar;
The angle α between the side of the transverse rib and the surface of the steel bar shall not be less than 45 degrees;
The sum of the gaps (including the width of longitudinal ribs) between the ends of transverse ribs on two adjacent sides of the steel bar shall not be greater than 20% of the nominal perimeter of the steel bar;
When the nominal diameter of the steel bar is not more than 12mm, the relative rib area should not be less than 0.055; when the nominal diameter is 14mm and 16mm, the relative rib area should not be less than 0.060; when the nominal diameter is greater than 16mm, the relative rib area should not be less than 0.065. Refer to Appendix C for calculation of relative rib area.
Ribbed steel bars usually have longitudinal ribs, but also without longitudinal ribs;
3) Length and allowable deviation
A. Length:
Steel bars are usually delivered in fixed length, and the specific delivery length should be indicated in the contract;
Reinforcing bars can be delivered in coils, and each reel should be one rebar, allowing 5% of the number of reels in each batch (two reels if less than two) consisting of two rebars. The disk weight and disk diameter are determined through negotiation between the supplier and the buyer.
B. length tolerance:
The allowable deviation of the length of the steel bar when it is delivered to a fixed length shall not be greater than ±25mm;
When the minimum length is required, its deviation is +50mm;
When the maximum length is required, the deviation is -50mm.
C. curvature and ends:
The end of the steel bar should be sheared straight, and the local deformation should not affect the use.
