(1) The steel used for corrugated beams, columns, crossbeams, end caps, and connecting bolts shall be ordinary carbon structural steel (Q235), and its technical specifications shall comply with the provisions of "Carbon Structural Steel" (GB 700).
(2) Splicing Bolts. Corrugated beams are tension members, requiring high-strength bolts for splicing to significantly enhance the strength at the joints. It is recommended to use No. 45 steel or 20MnTiB steel for high-strength bolts, conforming to the provisions of "High-Strength Torque-Shear Bolt Connections for Steel Structures" (GB 3632～3633): yield strength > 990MPa, tensile strength > 1100MPa, elongation ≥ 10%, and shrinkage rate 42%.
The heads of high-strength bolts can be formed by cold working or hot working, using a rolling method to form the threads, followed by quenching in a salt bath furnace or roller hearth furnace. The quenching temperature should be selected between 860°C and 880°C, followed by tempering in a nitrate furnace at 340°C to 380°C to improve its strength and hardness. To enhance the rust resistance of high-strength bolt connections and improve lubrication between bolts and nuts, their surfaces should be properly lubricated. Nuts for high-strength bolts should preferably be made of No. 35 steel and undergo appropriate heat treatment. The physical properties of No. 35 steel should meet the requirements of the "Technical Conditions for High-Quality Carbon Structural Steel" (GB). The relevant provisions of 699) shall apply.
Nuts should preferably be hot-forged and processed after heat treatment. Nuts should be lubricated.
Washers should be continuously punched from flat steel or strip steel. Since the bearing surface of the washer is an important factor affecting the torque coefficient, special attention should be paid to the smoothness of the surface when selecting materials, and attention should be paid to the various performances of the punching and flattening machines used for punching and shaping the washers. The manufacturing process of washers is: material selection → punching → punching → forging → grinding → heat treatment → finished product.
(3) Anti-blocking blocks. Anti-blocking blocks can be made of profile steel, and the steel should comply with the provisions of "Carbon Structural Steel" (GB 700). Its technical conditions should comply with the provisions of "Technical Conditions for Cold-Formed Steel" (GB 6725).
(4) When the column is embedded in concrete, the concrete grade should not be less than 15. The concrete material should comply with the current transportation industry standard "Technical Specifications for Construction of Highway Bridges and Culverts" (JTJ). According to the provisions of 041).
Material Corrosion Protection: All cold-formed steel components of corrugated beam guardrails should undergo anti-corrosion treatment, generally hot-dip galvanizing. The zinc used for hot-dip galvanizing should be No. 0 or No. 1 zinc as specified in "Zinc Ingots" (GB 470).
After hot-dip galvanizing, bolts, nuts, and other fasteners must have their threads cleaned or undergo centrifugal separation. Where conditions permit, bolts, nuts, and other fasteners can also be treated with powder coating.
The anti-corrosion treatment of movable guardrails is in principle the same as that of corrugated beam guardrails. When using hot-dip galvanizing, the zinc coating amount is specified as 600g/m2. In areas where steel is severely abrasive, hot-dip aluminizing, dip coating, and powder coating methods can be used. Localities can choose the appropriate method based on local conditions and economic and technical comparisons. When using hot-dip aluminizing, the coating amount can reach 110-120g/m2. In areas with particularly severe corrosion or for aesthetic purposes, guardrail steel components can be coated with plastic or painted after galvanizing.