Convex & Concave Curved Guardrail Panels

Gregory Highway’s curved guardrail sections can be installed on curves having a radius of 5 feet to 150 feet. Panels can be pre-curved either convex or concave in our fabricating facilities prior to delivery. Terms "convex" or "concave" refer to the direction curved, inward or outward, relative to the traffic face of the guardrail.

How to Find the Radius of Curved Guardrail

1. Starting at the last post in the straight run (Point A), lay a cloth tape along the path that the curved guardrail will follow.
2. Mark-off two points along the curved cloth tape: one at 6'-3'', (Point B) and the second at 12'-6'' (Point C)
3. Pull strong directly from starting point (Point A) to the second mark-off point (Point C).
4. Measure from the first mark-off point (Point B) over to the mid-point of the taut string. This measurement (D) is the rise.
5. Check the guardrail radius chart below to find the radius (R), given the rise (D). Example: A rise of 3-7/8'' would result in a radius of 60 feet.

Note: Follow the steps above for each piece of guardrail section in the curved run.

The arc may not be consistent, and each consecutive piece of guardrail may differ in radius from the previous one.

 

 

Guardrail Radius Chart

Functions of 12-ft., 6-in. Arc For Different Radii

 

Radii (R)	Angle (A)	Chord (C)	Rise (H)
5	143° 14	9'-5 7/8"	3'-5"
10	71° 37'	11'-8 3/8"	1'-10 3/4"
15	47° 45'	12'-1 3/4"	1'-3 3/8"
20	35° 49'	12'-3 5/8"	11 5/8"
25	28° 39'	12'-4 1/2"	9 3/8"
30	23° 52'	12'-4 7/8"	7 3/4"
35	20° 28'	12'-5 1/8"	6 5/8"
40	17° 53'	12'-5 3/8"	5 7/8"
45	15° 55'	12'-5 1/2"	5 1/4"
50	14° 19'	12'-5 5/8"	4 5/8"
55	13° 01'	12'-5 5/8"	4 1/4"
60	11° 56'	12'-5 3/4"	3 7/8"
65	11° 01'	12'-5 3/4"	3 5/8"
70	10° 14'	12'-5 3/4"	3 3/8"
75	9° 33'	12'-5 3/4"	3 3/8"
80	8° 57'	12'-5 7/8"	3"
85	8° 26'	12'-5 7/8"	2 3/4"
90	7° 58'	12'-5 7/8"	2 5/8"
95	7° 32'	12'-5 7/8"	2 1/2"
100	7° 10'	12'-5 7/8"	2 3/8"
110	6° 31'	12'-5 7/8"	2 1/8"
120	5° 58'	12'-6"	2"
130	5° 31'	12'-6"	1 3/4"
140	5° 07'	12'-6"	1 5/8"

 

AASHTO Specifications

Our guardrail is manufactured to AASHTO specifications in M180 Class A or B, and finish types 1, 2, 3, or 4. Every piece of Gregory Highway guardrail is stamped with a brand registration that is repeated throughout the entire length of the rail.

Gregory Stamping Code:

1. Manufacturer: GH=Gregory highway
2. AASHTO Specifications
3. Mill Heat Number Code
4. Galvanized Lot
   • 09 = Week (9th week)
   • 07 = Year (2007)
5. Class
   • Class A = 12 gauge
   • Class B = 10 gauge
6. Type
   • Type 1 = Zinc coated 1.8 oz/sq. ft. (550 g/sq. m.) minimum single spot
   • Type 2 = Zinc coated 3.6 oz/sq. ft. (550 g/sq. m.) minimum single spot
   • Type 3 = Uncoated Steel
   • Type 4 = Weathering Steel