Guardrail bolts are designed to attach W-beam and thrie-beam guardrail panels to wood or steel posts, as well as to splice rail sections together. They are installed through pre-punched oval slots in the guardrail, ensuring proper alignment and ensuring the guardrail is properly aligned. Guardrail bolts are manufactured to meet the chemical and mechanical requirements of ASTM A307 Grade A. Highway guardrail installations are typically state and federally funded DOT projects following the rules of the Buy America Act and using steel that is melted and manufactured in the USA.

To withstand outdoor exposure, guardrail bolts, double recessed nuts, and plate washers are hot-dip galvanized in accordance with ASTM F2329 and ASTM A153, providing long-term corrosion protection.

• Splice Bolts: Used to connect overlapping sections of guardrail panels end-to-end. The oval neck design locks into the rail slot to prevent rotation. Standard size: 5/8” × 1-1/4”. Proper installation is critical for guardrail performance in collisions.

  
  

• Post Bolts: Used to fasten the W-Beam guardrail panels to vertical posts. Longer than splice bolts, they typically start at 2″ with specialty applications requiring extended lengths up to 46″.

  
  

Grades/Specs: 

The AASHTO M 180 specification covers steel components used in highway guardrail applications, including bolts, nuts, washers, guardrail beams, end sections, terminal connectors, backup plates, guardrail posts, and anchorage wire rope and swage fittings. Guardrail splice bolts and post bolts are typically manufactured to meet the chemical and mechanical requirements of ASTM A307 Grade A and are hot-dip galvanized for enhanced corrosion resistance.

Our Guardrail Bolt Stock

Portland Bolt Northeast stocks thousands of post bolts and splice bolts, which are available for immediate shipment. 

Custom Guardrail Bolt Sizes

While we keep the most popular items readily available for immediate purchase, we also supply special order non-stock sizes.