The shape of the transverse ribs is spiral, herringbone, and crescent. It is expressed in millimeters of the nominal diameter. The nominal diameter of ribbed steel bars is equivalent to the nominal diameter of smooth round steel bars with equal cross-sections.

The nominal diameter of the steel bars is 8-50 mm, and the recommended diameters are 8, 12, 16, 20, 25, 32, and 40 mm. Ribbed steel bars mainly bear tensile stress in concrete. Ribbed steel bars have greater bonding capacity with concrete due to the action of ribs, so they can better withstand external forces. Ribbed steel bars are widely used in various building structures, especially large, heavy, light thin-walled and high-rise building structures.