How To Find The Radius For A Curved Rail
The diagrams & chart provide date for locating posts and curves.
- STEP 1: Starting at the last post in the straight run (point A), lay cloth tape along the path that the curved guardrail will follow.
- STEP 2: Mark-off two points along the curved cloth tape: One at 6’-3”, or 1905 mm (point B) and the second at 12’-6” or 3,810 mm
- STEP 3: Pull string directly from starting point (point A) to the second mark-off point (point C).
- STEP 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.
- STEP 5: Check the chart to find the Radius (R), given the Rise (D). Example: a Rise of 4 inches (102 mm) would result in a radius of 60 feet (183 m).
Note: Follow the steps for each piece of rail section in the curved run. The arc may not be consistent and each consecutive piece of rail may differ in radius from the previous one. Please consult with an individual approved by the governmental authority specifying and supervising the installation of the guardrail.