The nominal diameter of the steel bar is 8-50 mm, and the recommended diameters are 8, 12, 16, 20, 25, 32, 40 mm. Steel bars mainly bear tensile stress in concrete. Due to the effect of the ribs, the deformed steel bar has a greater bonding capacity with the concrete, so it can better withstand the external force. Steel bars are widely used in various building structures. Especially large, heavy, light thin-walled and high-rise building structures.