Highway Guardrail Posts: H, Sigma, U, C & Round Sections
What a Highway Guardrail Post Has to Do
A guardrail post carries the rail, holds it at the right height and passes the impact load into the ground. The post section is part of the tested system: the rail, the blockout or spacer, the bolt pattern and the post all work together. Changing one of them without the engineer's approval can take the barrier outside the configuration it was crash tested in, even when every individual part looks correct.
We roll, punch and galvanize H, Sigma, U, C and round posts for W-beam and thrie-beam projects in Shandong, China, and supply them together with the rails, spacers, bolts and end terminals so that every hole lines up on site.
Highway Guardrail Post Sections Compared
| Post type | Section and size | Length range | Typical use |
|---|---|---|---|
| H post | W150×13.5 wide flange, 150 mm deep | 1830 / 1980 mm | AASHTO M180 W-beam and thrie-beam runs |
| Sigma post | Sigma 100 (100×55), Sigma 150 (150×100) | 1500–2300 mm | EN 1317 style barriers, softer ground |
| U post | U140 / U150 / U178 channel | 1200–2000 mm | Low-speed roads, temporary and permanent barriers |
| C post | C100 / C125 / C150 with 25 mm lips | 1200–2200 mm | Highway barriers where the drawing calls for a channel section |
| Round post | Φ114 / Φ140 tube | 1200–2500 mm | Thrie-beam, roller barrier, bridge and industrial sites |
The profiles are not interchangeable. A Sigma 100 and a Sigma 150 have different depths and stiffness, and an H post cannot simply replace a U post on an approved drawing. If the section is unavailable, ask the project engineer for a written substitution before ordering. Our guardrail post types guide covers the differences in more detail.
Steel, Wall Thickness and Zinc Coating
- Steel grade: Q235B or Q345B for the Asian and Middle East markets, or the grade named in the project specification.
- Wall thickness: 4.0–6.0 mm for roll-formed U, C and Sigma posts, 3.0–6.0 mm for round tube. Thinner sections are available, but they change the stiffness of the system.
- Coating: hot-dip galvanized to 550 g/m² (Type I) as the standard, or 1100 g/m² (Type II) for coastal, high-humidity and de-icing-salt routes, tested to ASTM A123 or ISO 1461.
- Holes: punched before galvanizing, typically 20 mm round or slotted holes for M16 bolts. Never drill a galvanized post on site without touching up the coating.
Coating weight is the item most often written loosely in a BOQ. State the minimum g/m² and the test standard, otherwise quotations that look similar can differ by a full coating class.
Post Spacing, Embedment and Foundation
Two metres and four metres are the common spacing values on highway barriers, but the number that matters is the one on the approved drawing, because spacing is part of what the system was crash tested at. The same applies to post length: the drawing fixes both the height above ground and the embedment depth. Posts may be driven, set in a concrete footing or bolted to a base plate, and the foundation method decides what the post length and any base plate detail should be. Do not cut posts to length on site to make them fit.
How to Specify Highway Guardrail Posts in an RFQ
- Post section and the drawing number, for example W150×13.5 H post.
- Length, and whether it is the total length or the length above ground plus embedment.
- Steel grade, or a mechanical property requirement.
- Coating weight in g/m² and the test standard.
- Hole pattern, hole size and bolt size, with the spacer or blockout that goes with it.
- Quantity, destination port and the required delivery date, so packing and container loading can be quoted at the same time.
Send the drawings and BOQ through the contact page and we will check post and rail compatibility before quoting, including the bolts, washers and spacers that the system needs.
Highway Guardrail Posts FAQ
How do I choose between H, Sigma, U, C and round posts?
Follow the tested system named in the approved drawing. The section is not a free choice: it decides the bolt pattern, the rail height and how the load reaches the ground. Only substitute when the engineer approves it in writing.
What post spacing should I specify?
Two metres and four metres are the usual values, but take the figure from the approved drawing and the crash test the barrier was qualified to. Spacing and post section are tested together.
What zinc coating do highway guardrail posts need?
550 g/m² is the normal specification and 1100 g/m² is used for coastal, humid or salted roads. Name the standard — ASTM A123 or ISO 1461 — and the minimum coating weight, not just "galvanized".
Can I buy posts from one supplier and rails from another?
It is possible, but the hole pattern, bolt size and spacer must match exactly, and responsibility for a mismatch is unclear when two factories are involved. Supplying the beam, post and accessories together keeps the system consistent.
Why is a thrie-beam post longer than a W-beam post?
The thrie-beam rail is 510 mm tall against about 310 mm for a W-beam, so the post has to extend higher to hold the rail at the same finished height. That is why an H post is normally 1980 mm for thrie-beam and 1830 mm for W-beam.
Specifications and Project Requirements for Highway Guardrail Posts
Before requesting a quotation, confirm the post profile, dimensions, length, steel thickness, steel grade, hole pattern, surface treatment, post spacing and foundation or embedment method. C posts, U posts, H posts, Sigma posts and round posts must match the selected guardrail beam, blockout and bolt system.
Request a Quote for Highway Guardrail Posts
Send the project country, applicable standard, approved drawings, BOQ, post type, quantities, coating requirement and destination port. SinoGuardrail will review component compatibility, production details, packing method, container quantity and delivery schedule before quotation.
