Guardrail Barrier Complies with AASHTO M-180 Standard
Guardrail barrier in AASHTO M-180 standard clearly stipulate the classification, materials, mechanical properties, coating requirements and ordering information of highway guardrail. The details are below:
Highway guardrail can be produced according to types and classes of AASHTO M-180 standard,which has well mechanical properties.
Four types and two classes of guardrail are provided follows:
|Type I—Zinc coated, 550g/m2 minimum single-spot.
Type II－Zinc coated, 1100g/m2 minimum single-spot.
Type Ⅲ－Beam to be painted.
Type Ⅳ－Beam of corrosion resistant steel.
|Class A: Base metal nominal thickness—2.67 mm.
Class B: Base metal nominal thickness—3.43 mm.
- A 307, Standard Specification for Carbon Steel Bolts and Studs, 60000 psi Tensile Strength.
- A 653 / A 653M, Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process.
- F 376, Standard Specification for Carbon and Alloy Steel Externally Threaded Metric Fasteners.
The mechanical properties of the base metal shall conform the following requirements:
- Beams and transition sections:
Yield point, minimum 345 MPa (50000 psi).
Tensile strength, minimum 483 MPa (70000 psi).
Elongation in 50 mm (2 in.), minimum 12 %.
- End and buffer sections:
Yield point, minimum 227 MPa (33000 psi).
Tensile strength, minimum 310 MPa (45000 psi).
Type I and Type II beams:
The beams may be galvanized before after fabrication.
The mass of coating shall conform to the requirements in the following table for the types specified. The mass of coating is the total amount of galvanizing on both sides of a sheet or beam, expressed as g/m2 (& oz/ft2) of sheet.
|Model||Min Check Limit Single-Spot Test||Min Check Limit Triple-Spot Test|
Orders for guardrail under this specification shall include the following information, as required, to adequately described material:
- Quality (linear meter or number of pieces).
- Class of guardrail.
- Types of guardrail.
- Effective length of beam section 3.8 mm or 7.6 mm.
- Shape (W-beam or Thrie-beam).
- Exceptions to this specification or special requirements, if any.